New Delhi: Delhi's air quality improved marginally on Tuesday but remained in the 'poor' category, according to monitoring agencies.

The city's 24-hour average Air Quality Index (AQI) stood at 220, improving from 263 at 4 pm on Monday.

The 24-hour average AQI settled at 218 in neighbouring Ghaziabad, 179 in Faridabad, 158 in Gurugram, 170 in Noida and 248 in Greater Noida.

An AQI between zero and 50 is considered 'good', 51 and 100 'satisfactory', 101 and 200 'moderate', 201 and 300 'poor', 301 and 400 'very poor', and 401 and 500 'severe'.

On Sunday, Delhi's air quality turned 'very poor' for the first time since May, mainly due to a drop in temperature and wind speed, which allowed pollutants to accumulate. A few incidents of firecracker burning were also reported from parts of Delhi on the occasion of Dussehra on Tuesday.

In accordance with the practice of the last three years, Delhi had last month announced a comprehensive ban on the manufacture, storage, sale and use of firecrackers within the capital city.

A public awareness campaign, 'Patakhe Nahi Diye Jalao', will be soon reintroduced to discourage burning of firecrackers.

Unfavourable meteorological conditions and a cocktail of emissions from firecrackers and paddy straw burning, in addition to local sources of pollution, push Delhi-NCR's air quality to hazardous levels around Diwali every year.

On Monday, Delhi Environment Minister Gopal Rai said the government has identified eight more pollution hotspots in addition to the existing 13 in the national capital and special teams will be deployed there to check pollution sources.

Rai said the government has also decided to use suppressant powder to prevent dust pollution in the city.

Dust suppressants could include chemical agents like calcium chloride, magnesium chloride, lignosulfonates and various polymers. These chemicals work by attracting and binding fine dust particles together, making them too heavy to become airborne.

The minister also said the government will relaunch a campaign to curb vehicular pollution on October 26, a year after Lieutenant Governor (LG) V K Saxena put it on hold, questioning its effectiveness.

Sources in the city government's environment department said the LG's permission will not be required for the "Red Light On Gaadi Off" campaign this year as the participants will not receive any honorarium, unlike in previous seasons.