But how much does burning of crop residues contribute to Delhi’s pollution peaks? There are no definite answers. About 80% of Delhi’s pollution is due to reasons that are restricted within the national capital’s limits, while the rest is due to crop burning, India’s environment minister Anil Madhav Dave said on Monday after a meeting with neighbouring states.

According toAnumitaRoychowdhury, executive director at the Delhi-based Centre for Science and Environment, no exact figure is available.

“Stubble burning is an episodic problem which contributes to the pollution peaks in Delhi but even after the burning stops, in December, Delhi witnesses very high pollution,” she said, adding, “Delhi’s own pollution due to 8.8 million cars, constant construction activities and power plants are also major factors.”

There are some other figures, too. GufranBeig, programme director of System of Air Quality and Weather Forecasting and Research (SAFAR) of the earth sciences ministry told the Times of India on Monday that the proportion of pollutants from crop fires in Delhi’s air rose dramatically from almost zero on 1 November to a peak of 70% on 6 November.

Even if crop fires are a major threat to Delhi’s air, can farmers be blamed? Some experts said the problem was created by new technology. “Stubble burning started with the use of combine harvesters (some 15 years ago) and a solution has to be found in technology itself,” said Devinder Sharma, Chandigarh-based food policy analyst and convenor of KisanEkta, a pan-India forum of farm unions.

As giant combines harvest the crop, it leaves behind a stubble, about 6-8 inches long. Farmers then burn the stubble as it makes no sense to manually harvest the stubble since it cannot be used as animal fodder. Also, manual harvesting of paddy costs over Rs.4,000 per acre compared to Rs.1,200 by using combines.

“Manufacturers of these machine or public research institutes have to step up their R&D to ensure that the machine doesn’t leave the stubble behind or that the biomass can be gathered by attaching some other machines to combines,” Sharma said.

The solution lies in using a baler which can collect the straw neatly, said Anil Menon, head of market development at CLAAS, a leading manufacturer of farm machinery. “But the government has to put in place the right financial incentives and ensure the collected straw can be used in biomass plants (for power generation).”

A baler costs about Rs.11 lakh, not easy for an individual farmer to invest in. “With subsidies for balers and setting up of biomass-based power plants, using a baler can be viable for contractors who rent out farm machinery,” Menon said.

In December last year, then environment minister Prakash Javadekar met environment ministers of five states and decided on an action plan. One measure was to “take steps for setting up of biomass based power generation units to avoid biomass burning” within a year.

More than 10 months have passed without any action.

Why blame farmers or penalize them then?