Urbanisation Challenges and Measuring Growth

Why rapid growth creates pressure in Mumbai

Mumbai lies on India's western coast beside the Arabian Sea. Its economic opportunities attract people, but increasing population also increases demand for homes, employment, transport, water and sanitation. If provision cannot expand quickly enough, shortages develop. The challenge is not simply having a large population: it is the mismatch between growing demand and the capacity to meet it.

Provision also varies within the city. Some residents have good-quality housing and reliable services, while others experience overcrowding and insecure access to essentials. Malabar Hill is a wealthy residential area, whereas Dharavi contains densely packed housing alongside extensive small-scale industry. These contrasts mean that Mumbai's economic importance does not guarantee good living conditions for everyone.

Housing, infrastructure and services are connected

Many low-income migrants cannot afford formal housing. A shortage of affordable homes encourages people to construct housing from salvaged materials in informal settlements. Such homes may not meet building standards, and infrastructure may be added irregularly rather than planned before construction.

Closely packed homes allow fires to spread rapidly. Unsafe electricity connections create additional dangers and can contribute to power cuts. This links a housing problem to an infrastructure problem: a roof alone does not provide a safe home if the electricity supply is hazardous.

Narrow lanes can prevent public transport from entering settlements and make access difficult for emergency services. Residents of peripheral settlements may also face long journeys to schools and employment. However, informal settlements are not all on the outskirts: Dharavi is an established area within Mumbai. Location and accessibility therefore affect the challenges experienced by different communities.

Services are the activities provided for people, such as education, healthcare and waste collection. Infrastructure enables many of these services to function. For example, accessible roads help emergency vehicles reach residents, while sewers help protect public health. Poor provision in one area can therefore worsen several aspects of daily life at once.

Employment does not always provide security

A growing city can offer employment without providing enough secure, well-paid jobs for all its residents. Informal employment includes work outside full official regulation, often without a formal contract. In Dharavi, recycling and rag-picking process waste from the rest of Mumbai, providing livelihoods and a useful economic service.

The case-study estimate of around 20,000 small factories and sweatshops in Dharavi shows the scale of local industry. Working conditions vary: some workers receive fair wages, while some workplaces employ children or do not follow building regulations. Informal work should therefore not be treated as either entirely harmful or automatically secure. It can provide income while leaving workers poorly protected.

Under-employment is different from unemployment. An unemployed person has no job; an under-employed person has work but cannot obtain enough hours or work that fully uses their skills. For example, someone seeking a full working week but finding only occasional jobs is under-employed. An income that is too low or irregular makes it harder to afford safe housing and everyday necessities.

Analysis of India's National Sample Survey estimated under-employment in Mumbai by comparing employment measured over a week with employment measured day by day. Someone can count as employed during a week while still having days without work. Across the survey rounds examined, the estimated under-employment rate varied between 5 and 10 per thousand males aged 15 and above, and between 4 and 14 per thousand females aged 15 and above. These are historical estimates, not current rates, but they demonstrate that having some employment does not necessarily mean having enough work.

The 2007–08 survey also shows differences in the amount of work obtained: Mumbai's casual wage labourers averaged 5.4 working days per week, compared with 6.9 days for regular salaried or wage employees. Fewer working days alone do not prove that every casual worker wanted more work, but the contrast helps explain why irregular employment can leave households with less dependable earnings. Casual work means work obtained on an irregular basis; it is not automatically the same as informal employment.

Pollution and overcrowded transport affect health

Inadequate sanitation links housing conditions to water pollution. Sewage entering Mumbai's Mithi River contaminates water. Exposure to contaminated water can spread water-borne illnesses, including typhoid and diarrhoeal disease. This is both an environmental challenge, because water quality deteriorates, and a social challenge, because people's health suffers.

Transport faces pressure too. Congested roads and expensive car ownership encourage many workers to depend on trains. Overcrowding creates dangerous conditions, including the risk of falling from trains, contact with electrical cables and accidents when crossing tracks. Transport capacity therefore affects more than journey times: it also affects safety and access to employment.

These challenges reinforce one another. Low or insecure earnings restrict housing choices; inadequate housing and sanitation increase health risks; illness can then interrupt work and reduce income further.

Reading a population line graph

A population line graph places time on the horizontal axis and population on the vertical axis. First check the dates, units and geographical boundary: a city's administrative area and its wider urban region may have different populations.

A rising line shows population growth. A steeper upward section shows a faster absolute increase per unit of time, provided the axis scales stay the same. To quantify that change, read the population at both ends of the interval rather than relying only on the line's appearance.

Data for Measuring population growth over two decades

Its fictional city grows from 10 million people in 2000 to 12 million in 2010. The increase is 2 million over ten years, so:

$$\text{Average annual increase}=\frac{\text{population increase}}{\text{number of years}}=\frac{2}{10}=0.2\text{ million people per year}$$

Percentage growth measures the increase relative to the starting population:

$$\text{Percentage growth}=\frac{\text{final population}-\text{starting population}}{\text{starting population}}\times100$$

For 2000–2010, this is $\frac{12-10}{10}\times100=20\%$ over the decade. Dividing this by ten gives an average of 2% of the starting population per year; this is not a compound annual growth rate.

For 2010–2020, the increase is 3 million and the decadal percentage growth is $\frac{15-12}{12}\times100=25\%$. Both the absolute annual increase and percentage growth are greater in the second decade.

Apply the same method to an actual city graph, but check whether later values are projections. A projection describes an expected future population, not an observed count.

Investigating spatial growth with GIS and images

Population growth and spatial growth are different. A city can gain people through denser occupation of existing buildings, or its built-up area can spread into surrounding land. A population graph alone cannot show where either change occurs.

GIS allows satellite images, historic maps and other spatial information to be displayed as layers covering the same locations. Comparing layers from different dates can reveal where the built-up edge has moved, where gaps have filled in and where land use has changed.

In this fictional demonstration, each square represents 1 km². Four squares are built up at the earlier date and six at the later date. Matching the two views shows that the two new built-up squares are on the eastern edge: the footprint has expanded eastwards by 2 km². This is an illustration of the method, not a map or measurement of Mumbai.

To transfer the method to real Mumbai material, compare dated images or maps of the same area, aligned at the same scale. Use a GIS overlay or transparency slider to match roads, coastlines and other recognisable features. Trace the earlier and later built-up boundaries, then identify land that became built up between the dates. An area-measurement tool can quantify the expansion.

Images can also suggest land-use zones. Dense small roofs may indicate tightly packed housing; large buildings with transport yards may suggest industry. These are clues, not proof: check them against mapped labels or other information before classifying a zone.

Cloud cover, shadows, different image resolution and different map conventions can obscure change. Images also cannot directly establish employment conditions or service quality. Combining spatial evidence with information about housing, infrastructure and work helps explain why the pattern of growth matters.