In a letter to Javadekar, Delhi environment minister Asim Ahmed Khan said a plan, as recommended by a high-powered committee headed by the then chief secretary of Delhi, was submitted in February.

He also requested the Centre to take a more holistic view by involving stakeholders from the entire national capital region (NCR) as air pollution knows no boundary.

"The action plan was limited to the areas in which the Delhi government can check the rise of air pollution. It focused on short-term and long-term measures to control air pollution in the capital," Khan said. He explained that as a follow-up, various government agencies, including DDA, corporations, NDMC and Delhi Police, have been drafting time-bound implementation plans.

However, the letter also stated that air pollution does not recognize geographical boundaries. "At any point, air pollution is contributed by several sources even from long distances. Since NCR is a contiguous area with high population density and multiple pollutant sources, it is difficult to pinpoint and isolate the sources of pollution in Delhi alone."

Khan referred to crop residue burning contributing to high levels of pollution in Delhi. "Scientific studies indicate Delhi is receiving pollution from neighbouring towns and industries present in NCR." Hence, comprehensive, coordinated and integrated efforts are required to improve the air quality in Delhi, he said.

The Delhi minister also requested Javadekar to convene a meeting of all NCR stakeholders as several towns of Haryana and Uttar Pradesh fall within the region. "May I request you to ask them to set up joint check posts within their territories to ensure that overloaded vehicles can be turned back before entering Delhi." These states, Khan added, should also be asked to draft an action plan on the lines of that of Delhi to sort out problems of air pollution, sewage treatment and solid waste.