The chief ministers of Delhi and Haryana on Wednesday pledged to take all necessary steps to keep air pollution and smog under check in the National Capital Region, ANI reported. “We had a very positive discussion, and we will take all steps possible to tackle the situation,” Delhi Chief Minister Arvind Kejriwal said.

The situation in Delhi was a matter of concern for other states too as it is the national Capital, Haryana Chief Minister Manohar Lal Khattar said after meeting Kejriwal in Chandigarh. The two chief ministers said they have “jointly identified action points” to tackle the problem.

During the meeting, Khattar and Kejriwal discussed crop burning and vehicular pollution, and the Delhi chief minister promised that Gurugram would get 500 CNG buses, News18 reported. Crop burning is one of several factors that has caused the air quality to deteriorate in Delhi, Punjab and Haryana.

Punjab Chief Minister Amarinder Singh had refused to participate in the meeting, accusing Kejriwal of indulging in “petty street politics” to shift attention away from his failure to manage the dangerous levels of pollution. Kejriwal had claimed he had asked both the neighbouring states’ chief ministers for a meeting last week.

Delhi’s air quality improved slightly on Wednesday, a week after it had plummeted to the “severe” category and led to a public health emergency.