Every year, the issue of stubble burning in Punjab poses a significant challenge for its neighbours, particularly impacting Delhi and the National Capital Region (NCR), as these areas choke due to horrendous air quality.

While there might seem to be some positive news this year as the incidence of stubble burning appears to be slightly lower than in previous years, it’s too early for Delhiites to breathe easily yet.

This is because five-year data shows that while farm fires peak in November, NCR experiences its worst air from mid-December to the beginning of January.

The farm fire season

Farm fire incidents usually span between September 15 and November 30, and have fluctuated over the past few years. During this period in 2018, there were over 50,000 farm fire incidents in Punjab.

The following year, this number increased to over 55,000. In 2020, it reached its peak at more than 76,000. But the numbers began decreasing in 2021. As of November 15, 2023, there have only been around 30,661 stubble-burning cases.

Analysing five years of farm fire data, we found that even though the stubble-burning season technically starts mid-September with 20-50 incidents, the actual surge begins around September 27, when the number crosses the 100 mark. In October, farm fires reach thousands but the peak arrives in November.

In the first two weeks of November, the count usually skyrockets to more than 5,000. However, after this point, the number of farm fires begin decreasing, and usually by November 25, the count drops to under 100 incidents.

What did 2023 look like?

This year, too, saw a similar trend in Punjab. From mid-September to October, there were more than 7,000 farm fires. But things got concerning in early November when a sudden jump occurred, reaching more than 18,500 fires between November 1 and 13--a jump of 59 per cent and 70 per cent of all farm fires in the state in 2023.

Incidents dipped around Diwali but jumped to 2,544 on November 15.

How is this affecting air quality?

India Today’s Data Intelligence Unit analysed five years of data and found that in Delhi, the air quality usually starts declining from mid-October, with a consistent spike in air pollution levels in November. This, more-or-less, coincides with the stubble-burning season.

While there is a temporary decrease in pollution during the last two weeks of November, the levels start inching upwards from December. Subsequently, we see a spike in air pollution between the third week of December and the first week of January.

This increase in air pollution continues till the first week of February the following year, after which the air becomes more breathable. This shows that while stubble burning is one of the reasons for Delhi's pollution, it is not the sole cause.