Strategies for sustainability

A megacity has more than 10 million inhabitants. Providing its residents with water, housing, transport and essential services requires decisions at very different scales: a railway serves large parts of a city, while a community toilet block serves a neighbourhood.

Sustainable development means meeting present needs without compromising future generations’ ability to meet their own needs. In Mumbai, this involves improving quality of life while reducing pollution and managing resources effectively. A scheme is not necessarily sustainable simply because it builds something new: it must also be affordable, accessible and capable of being maintained.

Top-down and bottom-up approaches

In a top-down strategy, governments and other powerful organisations make major decisions and direct investment. They can coordinate expensive infrastructure across a whole city, including water supply, waste disposal, transport and air-quality improvements. However, decision-makers may prioritise prestigious projects over the everyday needs of poorer residents.

A bottom-up strategy starts with local communities identifying problems and helping develop solutions, often with support from a non-governmental organisation, or NGO. Local knowledge can make services more suitable and encourage residents to look after them. However, neighbourhood projects may depend on limited funding, volunteers and government permission. They cannot independently replace city-wide networks such as main sewers or railways.

Vision Mumbai: ambitious investment, unequal benefits

In 2003, the report Vision Mumbai proposed US$40 billion of investment to transform the city, with completion envisaged by 2050. Its partnership between government, property companies and investors made it a top-down approach.

Proposals included building one million low-cost homes, reducing slums, improving road and rail infrastructure, and reducing air and water pollution. Early targets included restoring 325 green spaces affected by pollution or waste dumping and building 300 additional public toilets. These were targets, rather than proof of completed improvements.

Housing redevelopment proposed replacing informal housing in Dharavi with high-rise blocks alongside offices, shopping malls and luxury apartments. New flats with piped water and sewerage could improve living conditions. Yet redevelopment also creates social and economic costs: higher rents can make housing less affordable, high-rise accommodation can split established communities, and relocating small workshops can threaten livelihoods, including recycling businesses.

This illustrates an important distinction: improving buildings does not automatically improve everyone’s quality of life. Residents who lose affordable accommodation, neighbours or nearby work may prefer improvements to their existing neighbourhood rather than demolition.

Transport and air quality: does the service meet people’s needs?

Mumbai’s government decided in 2005 to develop a monorail, followed by a public–private partnership in 2008. The first 9 km section opened in 2014, later than its planned 2011 deadline.

An elevated railway can carry passengers above congested streets without requiring a continuous route through buildings at ground level. If it provides a useful alternative to cars, public transport can also help reduce traffic-related air pollution.

However, the first monorail route carried only around 15,000 passengers per day, mostly tourists. Its route passed through an industrial area rather than directly into the old city, limiting its usefulness for many everyday journeys. Cheap fares alone were therefore insufficient: the location of the route mattered. The first section cost approximately £110 million, illustrating the large investment needed for a project whose initial use was limited.

Other rail improvements included 72 new trains by 2015 and raised platforms to reduce dangerous gaps between trains and platforms. These show how investment can improve both capacity and safety. More attractive public transport can help improve air quality if travellers switch from private vehicles, but investment alone does not establish how much traffic or air pollution has fallen.

Waste disposal: the Gorai Garbage Site Closure Project

From 1972 to 2007, around 1,200 tonnes of Mumbai’s solid waste arrived daily at Gorai. The dump occupied about 20 hectares and had reached approximately 27 metres in height. Decomposing waste released unpleasant smells and methane, while polluted liquid entered a nearby creek. These conditions damaged the environment and nearby residents’ quality of life.

Following a court order in 2007, the city government reshaped the waste, covered it with filling material to prevent leaching, and planted grass to create a 19-hectare park. Methane-capture technology was installed so that gas from decomposing waste could generate power.

The project tackled several problems together: covering the waste reduced pollution risks, the park provided a more pleasant environment, and capturing methane turned a waste product into an energy resource. The scheme received recognition for sustainable urban development in 2014. Nearby residents benefited from a cleaner environment, and property prices increased.

Nevertheless, closing and improving one dump does not remove the need to manage the waste produced elsewhere in the city. This is a strong local improvement, rather than a complete solution to Mumbai’s waste-disposal challenge.

Water supply: increasing capacity and improving distribution

A World Bank study found that Mumbai’s reservoirs held enough water to supply the megacity continuously, yet many areas, including the central business district, received water for only about six hours each day. Leaks in the city’s ageing pipe network were a major problem, and the lack of accurate network maps made repairs difficult.

This shows why water management must consider distribution as well as the amount stored. A successful city-wide strategy needs to get water reliably to users, not simply increase reservoir capacity.

Mumbai’s municipal government developed the Middle Vaitarna dam and conveyance system to increase supply. From 2014, the completed project supplied 455 million litres per day. Conveyance means transporting water from its source towards treatment facilities and users. In another completed improvement, the 15.1 km Gundavali–Bhandup Complex water tunnel was finished on 31 March 2017, supporting greater capacity and safer transport of water through the network.

These are advantages of top-down management: government can coordinate a dam, tunnels and distribution infrastructure at a scale beyond an individual community. Increasing supply and strengthening the network can support homes, businesses and essential services.

However, such engineering requires substantial funding and time. Difficult geological conditions slowed excavation on the separate Powai–Ghatkopar tunnel project. More supply also does not automatically eliminate unequal access. In its 2016–17 report, the municipal government still projected a demand–supply gap of 2,840 million litres per day for 2041, even after Middle Vaitarna. This was a forecast, not a measured shortage in 2041.

Water quality needs attention alongside quantity. Municipal laboratories tested around 200–250 samples daily, with more during monsoons or emergencies, and passed results to officials so that problems could be addressed. The city-wide percentage of unfit samples fell from 4.4% in 2014–15 to 3.0% in 2016–17. This indicates an improvement in sampled water quality, but does not prove that every household received safe, continuous water or that one particular project caused the change.

SPARC: community-led sanitation and health

SPARC is an Indian NGO working with Mumbai communities to build toilet blocks connected to city sewers and water supplies. Residents help construct the blocks, making this a bottom-up approach.

Earlier government-provided toilets charged for each visit, making repeated use expensive for families. They also suffered from poor design, a lack of running water and inadequate cleaning. SPARC’s approach addressed these practical barriers: families could buy a low-cost monthly permit, reported at about 25p, allowing unlimited use during that month. Electric lights made the blocks safer at night, and separate children’s toilets improved their suitability for families.

Access to toilets and sewer connections helps keep human waste away from living spaces, supporting cleaner conditions and better health. Community participation also makes the service more closely connected to residents’ needs. The reported programme provided 800 blocks, each containing eight toilets, over a five-year period.

Its limitations include delays in obtaining permits. It also depends on connections to city water and sewer networks: bottom-up action and top-down infrastructure are complementary, rather than completely separate alternatives.

Community-led housing: relocation with residents, not just for them

SPARC also works with the National Slum Dwellers Federation and Mahila Milan, an organisation of women from poorer communities, to help residents plan relocation. This alliance combines community organisation with negotiations involving government and infrastructure providers.

Residents carry out household surveys, check the information together and discuss relocation options. The surveys help identify affected families and support negotiations over housing and resources. The alliance also helps with moving, paperwork and the formation of residents’ societies. This matters because a household can lose access to work or services even when its replacement building is better.

In 1998, about 800 families living beside Mumbai’s Central railway tracks pioneered community-led relocation. Government provided land, the railways provided infrastructure, and residents built temporary transit housing and organised their own move. No police force was used. SPARC reports that another 12,000 households subsequently moved using the community-led strategy.

Under the Mumbai Urban Transport Project, affected families living beside railway tracks and roads were relocated to permanent homes with legal title. Legal title gives recognised ownership rights, providing greater housing security than an informal dwelling vulnerable to eviction. Relocation also enabled railway improvements while moving households away from dangerous trackside locations.

The advantage is meaningful resident participation rather than simply imposing a move. Yet it is not an independent solution: communities still need government land, infrastructure and cooperation. Organising surveys, resolving disputes and completing paperwork take sustained effort. New housing must also be judged by its location and access to livelihoods, not just its construction quality. The alliance’s approach therefore strengthens top-down investment, rather than replacing it.

Hamara Footpath: education shaped around disadvantaged children

Hamara Footpath began on Mumbai’s pavements in 2001, when a group of college friends started teaching local children. It is a voluntary organisation providing education for disadvantaged children, principally in the age groups 2–9 and 10–17, while also involving parents.

Its programmes include English, maths, computer literacy, life skills and financial competence. The organisation reports reaching more than 800 recipients. Teaching these skills can improve children’s learning opportunities and prepare them for further education and employment. Working with parents can help support learning beyond individual teaching sessions.

This is a bottom-up contribution to sustainability because it responds to the needs of disadvantaged families and invests in people’s longer-term opportunities. Its flexibility allows academic and practical skills to be taught together.

However, its reported reach remains small compared with a megacity’s population. Its work relies on a relatively small team of staff and volunteers and on financial support. It cannot replace city-wide education provision. Financial independence is an aim of the programme, not an outcome that can be assumed for every child who attends.

Using evidence to judge growth and quality of life

Historic maps and images can help explain how a city’s needs have changed. Mumbai developed from a small fishing port through nineteenth-century railway and cotton-trading growth, followed by textile manufacturing and later financial and service activities. When comparing historic material with modern maps or satellite images, first check dates, coverage and scale. Use recognisable features to align the views, then identify where built-up land has expanded or changed use. GIS can overlay mapped boundaries from different dates to make that comparison clearer.

For example, imagine an older map showing open land beside a railway and a later satellite image showing buildings in the same area. Aligning the railway and other unchanged landmarks would help establish where building has occurred. In GIS, tracing the built-up boundary at each date would show the added area. Apply this method to authentic dated material; the imagined example is not evidence of growth at a particular Mumbai location.

An increase in built-up land can indicate pressure on services, but an image cannot by itself establish household income, water reliability or residents’ satisfaction. These require other evidence.

Combine quantitative information, such as water-quality percentages, rents or passenger numbers, with qualitative information, such as residents’ accounts of affordability or community disruption. Mumbai’s water-testing figures show why the city average is not enough: in 2016–17, 9% of samples in ward A were unfit, compared with 1% in ward K/E. That is an eight-percentage-point difference between those two wards. Across all wards, values ranged from 0% in R/S to 9% in A: a range of nine percentage points. Both comparisons reveal substantial variation in this indicator despite the improved city average.

These percentages describe tested samples, not the percentage of residents who became ill. Residents’ experiences of supply interruptions or difficulty accessing services would help explain what the numerical differences mean for daily life.

Which approach is more effective?

Top-down strategies are strongest where improvements require large budgets and connected networks. Bottom-up strategies are strongest where local participation helps services fit everyday needs. Gorai demonstrates the potential of coordinated environmental action; Middle Vaitarna demonstrates large-scale water investment; SPARC demonstrates affordable sanitation and participatory housing; Hamara Footpath demonstrates targeted educational support. The monorail shows how a large project can disappoint when its route does not match users’ needs.

A balanced judgement considers environmental improvement, affordability, access, livelihoods and long-term maintenance. The most sustainable approach combines city-wide investment with meaningful community involvement.