FOUR THINGS TO KNOW ABOUT AUTUMN POLLUTION IN INDIA

As winter approaches each year, toxic smog envelops vast swaths of northern India, including the capital, New Delhi. This week, the Air Quality Index hovered above 475 on a scale of 500. Anything above 60 is considered unhealthy. Here's why air quality is so poor.

1 SEASONAL SITUATION

Air quality starts deteriorating by the end of October when lower temperatures, higher moisture and a drop in wind speeds trap pollutants in the atmosphere for longer. After the monsoon season ends in September, the wind direction changes, brings in dust, industrial emissions and vehicle exhaust. New Delhi has nearly 10 million vehicles, more than the other three major cities — Mumbai, Chennai and Kolkata — put together. Along with garbage burning, cold weather forces people, especially those spending the night in the open, to burn small fires to keep warm.

2 MOLEHILLS OUT OF MOUNTAINS

Large-scale mining for rocks and sand, used in construction, has hollowed out the Aravalli mountain range, a natural barrier that used to protect New Delhi from dust coming from the Thar Desert. Activists warn the fast disappearance of the Aravalli Range will make New Delhi more vulnerable to pollution woes.

3 FARMS AT SOME FAULT

In recent years, the problem has been exacerbated by the burning of crop residues in the farm belt that borders New Delhi. Relatively prosperous farmers from Punjab and Haryana, India's grain bowl, now have mechanized harvesters to gather the rice crop, partly to overcome the problem of rising labour costs. Unlike manual harvesting, mechanized harvesters leave stubble and rice-paddy straw in the field. Disposing of crop waste is time consuming, and after harvesting rice, farmers get only a short window to plant winter crops such as wheat and canola, and late sowing means lower yields. So farmers find it cheaper to burn the residue, which accounts for about a quarter of air pollution.

4 SOME GOVERNMENT AID

In 2018, India earmarked US$177.61 million for two years to give farmers a subsidy to buy equipment, such as mulching and seed drilling machines, that dispose of crop waste without burning it. For the 2020-21 fiscal year, the government allocated US$746.06 million in farm equipment subsidies. But farmers say lengthy bureaucratic processes to claim the subsidies forces them to burn their crop waste.