Lahore, Delhi choke as air pollution spikes in parts of South Asia

Air quality deteriorated sharply in Lahore and Delhi as pre-winter smog spread across northern India and adjoining Pakistan. Lahore recorded an AQI of 447, making it the world's most polluted city at that time. Delhi's readings also reached unhealthy levels, though different monitoring systems reported different numbers.

Authorities took several steps. Pakistan intensified action against brick kilns that violate environmental rules and urged farmers not to burn crop residue. Delhi introduced graded pollution controls, restricting polluting vehicles, construction, coal and firewood use in eateries, and expanding public transport.

Fireworks expected during Deepavali added concern in India. The Supreme Court allowed only low-polluting fireworks for three hours on Saturday and Sunday. These measures aim to reduce emissions while cold temperatures and weak winds continue trapping pollution near the ground.

The Air Quality Index, or AQI, is a numerical way to describe how polluted the air is and the health risk it may pose. The article notes that a reading up to 50 is considered good, with little or no health risk. Higher numbers indicate worsening air quality and greater concern for residents.

Lahore's AQI reached 447 according to IQAir. Delhi's IQAir reading was 215, while India's Central Pollution Control Board reported 332 and classified the air as very poor. These numbers show severe pollution, but they are not directly interchangeable.

The Swiss and Indian readings differed because they use different AQI scales, methods, and pollution classifications. The key point is that both cities faced hazardous air during the smog episode, exposing residents to serious respiratory risks.

Lahore's PM2.5 pollution reached an extraordinary level: its concentration was 60 times higher than the World Health Organization's annual PM2.5 exposure guideline. This comparison shows how far air pollution had moved beyond a level considered acceptable for long-term exposure.

PM2.5 means particulate matter measuring 2.5 microns or less in diameter. These particles are extremely small and can be carried deep into the lungs when people breathe polluted air. The article links exposure to deadly diseases and heart problems.

The figure also explains why Lahore's smog was a serious public-health emergency rather than only a visibility problem. Cold temperatures and sluggish winds had affected air quality, while emissions from vehicles, construction, and crop burning added pollution. Continued controls and reduced emissions are important as the season progresses.

Cold, dense air can trap pollution near the ground instead of allowing emissions to spread upward and disperse. This creates a layer of polluted air over cities. When winds are weak, fresh air moves slowly and pollutants remain concentrated in the same area.

The article describes this seasonal pattern as a major reason air pollution becomes severe around this time of year. Emissions from vehicles, construction sites, and crop waste burning collect in the lower atmosphere. Lahore authorities also linked deteriorating air quality to a significant temperature drop and sluggish winds.

This mechanism matters because people live and travel within the trapped layer. Pollution levels can rise rapidly even when emissions continue at familiar sources. The result is pre-winter smog, with very high AQI readings and serious respiratory risks for residents in Lahore, Delhi, and nearby areas.

The pollution had several human sources rather than one single cause. The article identifies vehicle emissions, construction activity, crop waste burning, brick kilns that violate environmental rules, and fireworks. These sources release pollutants that can accumulate over urban and surrounding areas.

Crop residue burning adds smoke after harvest, while vehicles and construction contribute emissions within cities. Brick kilns are another concern in Pakistan, prompting intensified government action. In India, fireworks during the Hindu festival of Deepavali were expected to worsen pollution, with the festival falling on November 8 that year.

Weather made these sources more damaging. Cold, dense air and sluggish winds trapped emissions close to the ground. This combination produced severe pre-winter smog, pushing Lahore's AQI to 447 and Delhi's air into very poor territory. Reducing several sources at once is therefore important.

Authorities are using restrictions and enforcement to reduce emissions before they accumulate. Delhi restricted polluting vehicles and construction, limited coal and firewood use in eateries, and boosted public transport. Pakistan intensified action against brick kilns that break environmental rules and urged farmers not to burn crop residue.

Each measure targets a specific source. Fewer vehicles can reduce traffic emissions, while pausing construction limits dust and other pollution. Replacing coal and firewood use cuts emissions from eateries. Stopping crop burning and controlling brick kilns reduce smoke outside cities. Public transport can support fewer polluting journeys.

Firework limits also matter. India's Supreme Court allowed only low-polluting fireworks for three hours on Saturday and Sunday around Deepavali. These steps cannot remove existing smog immediately, but they can reduce new pollution while cold air and weak winds trap emissions.

PM2.5 is particulate matter measuring 2.5 microns or less in diameter. Because these particles are so small, they can be carried deep into the lungs when inhaled. This makes high concentrations a serious health threat rather than merely a visibility or comfort problem.

The article states that PM2.5 exposure risks deadly diseases and heart problems. Heavy pollution also exposes residents to serious respiratory risks. During the episode, Lahore's PM2.5 concentration was 60 times higher than the World Health Organization's annual guideline, showing the scale of potential exposure.

People in affected cities were breathing this polluted air while cold, dense conditions and weak winds kept emissions near the ground. Reducing vehicle emissions, smoke, construction pollution, crop burning, and fireworks can lower the amount of PM2.5 entering the air and lungs.