New Delhi, Nov 21 (IANS): The air quality in Delhi and nearby areas has repeatedly hit dangerous level after winter started setting in post Diwali but official data shows number of relatively clean air days are on the rise.

Responding to calling attention motion in the Rajya Sabha, Union Environment minister Prakash Javadekar on Thursday said that there has been a general improvement in the air quality of Delhi in the last three years.

"The good, satisfactory and moderate days which were 106 in 2016 have improved to 152, now to 159 and I am happy to tell that out of 324 days of this year, 175 days are in this category. And bad air days have gone down from 246 to 213 to this year's 190 days out of 324," the Minister said.

He said that the data is based on the air quality index (AQI) monitoring stations.

The Minister said that the central government had notified a graded action plan after due consideration with concerned authorities. The plan is to be rolled out throughout the year depending on the air quality level in the national capital region (NCR).

In order to deal with the pollution which gets aggravated during the winter season, a source-based approach has been taken.

Among various sources of pollution, the minister said that the key of them are industry, vehicles, road and soil dust, construction and demolition, and garbage burning.

Around Diwali with wind speed coming down pollution level suddenly shoots up forcing the government to close schools and take other measures such as implementation of odd-even plan by the Delhi government to contain pollution.

With pollution becoming a major issue, lawmakers have been discussing plans to deal with it swiftly.

Talking about measures by the government to tackle air pollution in the country, the Environment Minister said that clear air programme has been launched since January, 2019.

On vehicular pollution becoming a major issue, Javadekar said that with migration to BS-VI compliant vehicles this will be curtailed to the extent of 80 per cent.