13 districts have been identified as hot spots of stubble burning in Punjab and Haryana.
Expecting a spike in Delhi air pollution in the coming days, the central government has directed Haryana and Punjab to stop stubble burning completely.
Environment Secretary CK Mishra said the next one week is critical for Delhi's air due to the festival of Diwali and stubble burning in neighbouring states.
"We have told Punjab and Haryana to completely stop stubble burning at least for the next few critical days. Next three weeks, especially days between October 26 to November 4, are critical and we are taking care," Mr Mishra said.
Through satellite technology, 13 districts have been identified as hot spots of stubble burning in Punjab and Haryana, he said.
"We have identified hot spots - 13 districts in Punjab and Haryana. Necessary measures like providing farmers the machines to prevent them from burning are required," he said.
When asked whether or not the Haryana government was buying cop residue from farmers as a measure to curb burning, Mr Mishra said only private players were doing so.
"Purchase (of stubble) is only happening in some areas by private entrepreneurs who are using it differently. NTPC, power companies are also buying. But that is not the solution. We have to push for in situ measures," he said.
The secretary also said though air quality is poor, it is not as bad as last year.
"Last year during this time, the air quality was ''severe''. Now it is oscillating between poor and very poor. There is discernable trend of improvement in the air," he said.
Mr Mishra said during the coming days, the "vigil" of authorities will be intensified to monitor air pollution in the capital.
The air quality in the national capital dropped to season's worst on Friday, with the decreased wind speed leading to accumulation of pollutants and affecting dispersion.
The city's overall air quality index (AQI) stood at 315 at 8:30 am on Friday, while it was 311 on Thursday evening.
Most of the places in the national capital recorded the AQI in the "very poor" category, while the situation inched towards "severe" in some areas.