NEW DELHI, Oct. 26 (Xinhua) -- Air pollution is worsening in the Indian capital and its nearby cities with each passing day.

Air quality in Delhi slided towards severe level Friday, with less than two weeks left for Diwali, the festival of lights, when pollution levels peak mainly because of bursting of fire crackers by revellers.

In the morning, air quality index (AQI) dipped to 358 from Thursday's 337, considered very poor category. An AQI between O and 50 is said to be good, 51 and 100 satisfactory, 101 and 200 moderate, 201 and 300 poor, 301 and 400 very poor and 401 and 500 severe.

Delhi's air quality has been hovering between poor and very poor categories since Monday. Its neighboring cities like Noida, Greater Noida, Ghaziabad, Gurgaon and Faridabad have also been experiencing high pollution levels for the past five days.

State-owned System of Air Quality and Weather Forecasting And Research (SAFAR) which monitors pollution levels has predicted very poor air quality in Delhi in the next 24 hours.

Alarmed at the situation, Delhi's Environment Minister Imran Hussain Tuesday reviewed an action plan for implementing the Graded Response Action Plan (GRAP). GRAP kicks in when AQI touches severe levels as mandated by the country's Supreme Court.

The country's Supreme Court has already ordered a partial ban on bursting of crackers during Diwali to keep pollution levels lower than in previous years. The court ruled that people can burst "green firecrackers" from 8 p.m. to 10 p.m. only on Diwali.