Air Pollution Crisis in Indian Megacities

India’s megacities faced air pollution crisis during the winter of 2024-25. Despite varying climates, cities like Delhi, Kolkata, Mumbai, Chennai, Hyderabad, and Bengaluru recorded alarming pollution spikes. The Centre for Science and Environment (CSE) brought into light this growing crisis and called for immediate action.

Current Pollution Levels

Delhi emerged as the most polluted megacity, with an average PM2.5 concentration of 175 µg/m³. This level is far above safe standards. The city experienced eight days of ‘severe+’ air quality and 12 days of ‘severe’ AQI. Kolkata followed with a PM2.5 average of 65 µg/m³, while Mumbai, Hyderabad, Bengaluru, and Chennai had lower averages. However, localised pollution levels in these cities spiked, with some areas exceeding city averages by 60%.

Trends Compared to Previous Years

Delhi’s winter pollution saw a 7% decline from 2023-24 but was still 5% higher than in 2021-22. Kolkata and Chennai showed little improvement. In contrast, Hyderabad recorded 51% drop in peak PM2.5 levels. Bengaluru also improved by 42%, while Mumbai and Chennai had modest reductions of 12% and 19%, respectively.

Localised Pollution Hotspots

Despite overall improvements in some cities, local pollution hotspots remain a concern. Areas like Deonar and Shivaji Nagar in Mumbai and IDA Pashamylaram in Hyderabad reported high PM2.5 levels. The CSE report emphasised that pollution from vehicles, industries, and construction activities contributes to these hotspots.

Need for Stricter Measures

The CSE urged cities to adopt stricter measures to combat air pollution. Anumita Roychowdhury, CSE’s executive director, called for a multi-pronged approach. This includes controlling emissions from vehicles, industries, and waste burning. Cities in the Indo-Gangetic Plain need even more stringent interventions due to adverse meteorological conditions.

Impact of the National Clean Air Programme

Despite five years of the National Clean Air Programme, improvements in air quality remain insufficient. While some cities have managed slight reductions, air quality still fails to meet national standards. The CSE report brought into light the need for urgent action to address pollution at its roots.

Seasonal Patterns of Air Quality

Seasonal analysis revealed that Delhi and Hyderabad faced the worst air quality in November. Mumbai peaked in December, while Kolkata, Bengaluru, and Chennai saw their highest pollution in January. The duration of poor air quality days was longest in Delhi, Kolkata, and Mumbai.

Call for Cleaner Policies

The report advocates for cleaner transportation policies and stringent industrial regulations. It also emphasises the large-scale adoption of clean energy sources to tackle air pollution effectively.

Questions for UPSC:

1. Examine the impact of urbanisation on air quality in Indian megacities.
2. Critically discuss the effectiveness of the National Clean Air Programme in improving air quality.
3. Point out the major sources of air pollution in metropolitan areas and their effects on public health.
4. Analyse the relationship between meteorological conditions and air pollution levels in urban environments.

Answer Hints:

1. Examine the impact of urbanisation on air quality in Indian megacities.

1. Rapid urbanisation increases vehicle emissions due to higher population density and transportation needs.
2. Construction activities contribute to dust and particulate matter in the air.
3. Industrial growth in urban areas leads to higher emissions of pollutants from factories.
4. Inadequate waste management practices result in burning waste, releasing harmful pollutants into the atmosphere.
5. Urban heat islands created by concrete and asphalt exacerbate pollution levels, trapping heat and pollutants.

2. Critically discuss the effectiveness of the National Clean Air Programme in improving air quality.

1. The National Clean Air Programme (NCAP) aims to reduce PM2.5 and PM10 levels across cities.
2. Despite its introduction, many cities still fail to meet national air quality standards.
3. Limited progress has been made in terms of long-term reductions in pollution levels.
4. Implementation issues, including lack of funding and local government engagement, hinder effectiveness.
5. The program needs stronger enforcement of regulations and a multi-faceted approach to address pollution sources.

3. Point out the major sources of air pollution in metropolitan areas and their effects on public health.

1. Vehicle emissions are a primary source, contributing to respiratory and cardiovascular diseases.
2. Industrial discharges release toxic pollutants, leading to long-term health issues among residents.
3. Construction activities generate dust and particulate matter, affecting air quality and health.
4. Waste burning emits harmful chemicals, increasing the risk of cancer and other illnesses.
5. Indoor air pollution from solid fuel use in homes poses health risks, particularly for women and children.

4. Analyse the relationship between meteorological conditions and air pollution levels in urban environments.

1. Temperature inversions can trap pollutants close to the ground, worsening air quality.
2. Wind patterns influence the dispersion of pollutants; stagnant air leads to higher concentration levels.
3. Humidity can exacerbate particulate matter, leading to increased health risks.
4. Seasonal variations affect pollution levels; winter often sees spikes due to heating and stagnant air.
5. Geographical features, like valleys, can trap air pollutants, particularly in cities like Delhi and Kolkata.