Why India’s farm fire counting method is disputed

A farmer burns stubble in a paddy field at Mansa in Punjab.
| Photo Credit: Reuters

India plans to count toxic farm fires by monitoring the burnt area they leave rather than the current method of using orbiting satellites to measure live fires.

Here is a look at how India counts farm fires – a major contributor to severe pollution in the north – and why its method is being questioned.

Why are farm fires lit?

Farmers in India light fires, in violation of laws that bar the practice, to quickly clear crop waste or stubble left behind after paddy is harvested so that they can plant wheat.

Although the government offers subsidies on harvesting machines that can replace this method, demand has been low due to their high price or long wait for those looking to rent them.

How does India monitor farm fires?

Officials say satellites are the only way to monitor farm fires since they capture a much larger area.

India’s space agency procures data from two orbiting NASA satellites that pass over the northern breadbasket states of Punjab and Haryana, among others, twice a day – around 10.30 am and 1.30 pm.

This is then shared with the government to count farm fires.

Is this method foolproof?

NASA satellites only capture instances of farm fires during the limited period when they are passing over the region, which takes them 90 seconds. They therefore only capture any blaze visible at that time or lit in the previous half hour.

Experts suspect that farmers have, over time, become aware of this surveillance period and shifted the time of burning their crop waste to evade the NASA satellites.

Why is it being questioned now?

An adviser to the Supreme Court, which is monitoring pollution management by authorities in the national capital region, this week said there was a discrepancy in the farm fire data obtained from orbiting and stationary satellites.

Citing information given by a senior scientist at NASA Goddard Space Flight Center, she said that a South Korean stationary satellite had captured farm fires at 4.20 pm (1050 GMT), well after the NASA satellites had moved on.

What is the alternative?

The court had directed the federal government to procure data of farm fires from stationary satellites as an alternative but the government said this data is “sub-optimal”.

Instead, India’s space agency is working on a system to count farm fires by studying the burnt area they leave behind.