🌫️ Pollution in India’s Major Cities: A Health-Focused Review

Introduction

Air pollution is a major public health crisis across India’s large cities. Short- and long-term exposure to fine particulate matter (PM_2.5), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ground-level ozone (O₃) and other pollutants increase the risk of cardiovascular, respiratory and metabolic diseases. This article—written from a health perspective—summarizes the main causes of urban pollution, the diseases it contributes to, evidence-based ways cities can manage pollution, and individual precautions to prevent illness.

1. Major Causes of Pollution in Indian Cities

Multiple sources, often acting together and amplified by seasonal weather, drive poor air quality in India’s metropolises:

• Vehicular emissions: Rapid motorization, high numbers of diesel vehicles, two-wheelers and in-use non-compliant vehicles emit NOx, CO, black carbon and PM.
• Industrial and power-plant emissions: Coal-fired power plants, small and medium industries and brick kilns release SO₂, NOx, primary PM and trace metals.
• Road, construction and resuspended dust: Construction sites, unpaved roads and uncovered transport of materials generate coarse and fine dust that adds heavily to PM₁₀ and PM_2.5.
• Biomass and open waste burning: Household biomass, garbage burning and seasonal crop-residue burning produce episodic spikes in PM levels—especially during winter.
• Meteorology and geography: Winter inversions, low wind speeds and long-range transport of smoke trap pollutants over cities and worsen air-quality episodes.

2. How Pollution Harms Human Health

Ambient air pollution affects nearly every organ system. Long-standing international and India-specific research shows substantial disease burden and premature mortality attributable to polluted air.

Cardiovascular system

Fine particulate matter (PM_2.5) increases systemic inflammation, promotes atherosclerosis and raises the risk of hypertension, ischemic heart disease, arrhythmia and stroke. Cardiovascular causes account for a large share of pollution-attributable deaths.

Respiratory system

Pollutants trigger and exacerbate asthma, cause chronic bronchitis and contribute to chronic obstructive pulmonary disease (COPD). Long-term exposure increases lung-cancer risk; short-term spikes raise acute respiratory infections and hospital admissions, particularly in children and older adults.

Neurological and cognitive effects

Emerging evidence links long-term exposure to PM_2.5 and NO₂ with cognitive decline, increased risk of dementia and poorer neurodevelopmental outcomes in children.

Metabolic and endocrine effects

Air pollution is associated with insulin resistance and a higher risk of type 2 diabetes—likely through chronic inflammation and oxidative stress pathways.

Reproductive and perinatal effects

Exposure during pregnancy has been associated with preterm birth, low birth weight and other adverse outcomes that may affect long-term child health.

Who is most vulnerable?

Children, older adults, pregnant women, people with pre-existing heart or lung disease, outdoor workers and socioeconomically disadvantaged groups face higher exposures and greater risks.

3. Diseases Commonly Linked to Urban Air Pollution

4. Ways to Manage City Pollution (Evidence-Based Interventions)

Effective management requires policy commitment, technical solutions, strong governance and public engagement:

• Transport and vehicles: Enforce stringent emission standards (e.g., Bharat Stage), conduct real-world on-road testing, incentivise electric vehicles while greening the electricity grid, and invest in high-quality public transport and non-motorised mobility.
• Industry and power sector: Retrofit emissions-control technologies, transition to cleaner fuels and move highly polluting units away from dense urban areas.
• Agriculture: Offer farmers alternatives to stubble burning (mechanised solutions, biomass markets) and create incentives to reduce open-field fires.
• Dust control: Mandate covered transport of construction materials, strict site dust-mitigation measures (water sprinkling, barriers) and regular street cleaning.
• Waste management: Stop open burning of municipal waste through segregation-at-source, improved collection, composting and scientific disposal.
• Monitoring and governance: Expand continuous monitoring, carry out city-level source apportionment studies and develop AQI-linked action plans and forecasting systems to trigger protective measures.

5. Personal-Level Measures & Health Precautions

Individuals can reduce exposure and lower their risk of pollution-related disease by adopting these practical steps:

Reduce exposure

• Monitor AQI: Use government and trusted apps to check air quality; avoid heavy outdoor exercise when AQI is in the "Unhealthy" or "Hazardous" range.
• Choose cleaner routes and times: Commute on less-polluted roads and avoid peak-traffic hours when possible.
• Use masks when required: Wear N95 / FFP2 masks outdoors during high-pollution days (ensure proper fit).

Improve indoor air

• Keep windows closed during severe outdoor pollution; ventilate when AQI improves.
• Use air purifiers with HEPA filters in bedrooms and common areas if feasible.
• Minimize indoor sources of pollution—avoid smoking at home and reduce use of mosquito coils or unvented gas stoves.

Protect health and build resilience

• People with asthma, COPD or heart disease should follow treatment plans, keep reliever inhalers accessible and consult physicians for action plans during pollution spikes.
• Maintain a balanced, antioxidant-rich diet (fruits, vegetables, omega-3s) and stay hydrated to support respiratory defenses.
• Get regular health checks—blood pressure, blood glucose and lung-function testing where indicated.
• Consider vaccinations (influenza, pneumococcal) if recommended by healthcare providers to reduce risk of severe respiratory infection during high-pollution seasons.

6. Conclusion

Air pollution in India’s major cities is a preventable health crisis. While systemic policy actions—cleaner energy, stricter emissions control, better urban planning and improved waste and agricultural practices—are essential, individual and community-level measures are also powerful. Protecting vulnerable groups, strengthening healthcare responses, and empowering people with timely AQI information are immediate steps that reduce disease burden while longer-term structural solutions take effect.

References & Further Reading

(Selected sources used to prepare this health-focused article)

1. World Health Organization — Ambient (outdoor) air pollution and health.
2. Lancet Planetary Health — Pandey A. et al., Health and economic impact of air pollution in India (Global Burden of Disease analyses).
3. Indian Council of Medical Research (ICMR) — Health of the Nation’s States / reports on pollution and health.
4. Centre for Science and Environment (CSE) — Urban air quality and vehicle emission studies.
5. Central Pollution Control Board (CPCB) — National Clean Air Programmed (NCAP) materials and city action plans.
6. Nature Sustainability — studies on crop-residue burning and seasonal pollution episodes.
7. Environmental Research / BMJ and other peer-reviewed journals — reviews on pollution links to diabetes, cognition and perinatal outcomes.