NEW DELHI, Oct. 29 (Xinhua) -- Air pollution continued to worsen in the Indian capital New Delhi ahead of Diwali, the festival of lights, with a thick haze engulfing parts of the city on Monday.

In the morning, air quality index (AQI) was recorded at 348, considered very poor category, according to the Central Pollution Control Board (CPCB).

An AQI between 0 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.

Pollution authorities attributed this to construction activities, vehicular pollution and stubble burning by farmers in the neighbouring states of Punjab and Haryana.

Last week, the CPCB recommended that people avoid heavy workouts, try to get themselves less exposed to toxic air, and cut down on the use of private cars at least for the next 10 days.

New Delhi's air quality has been hovering between poor and very poor categories since the past week though it has not yet formally reached the severe levels.

Its neighboring cities like Noida, Greater Noida, Ghaziabad, Gurgaon and Faridabad have also been experiencing high pollution levels for the past week.

State-owned System of Air Quality and Weather Forecasting And Research (SAFAR) which monitors pollution levels has predicted severe air quality in New Delhi in the next two days.

New Delhi's Environment Minister Imran Hussain had last week 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 ruled that people can burst "green firecrackers" from 8 p.m. to 10 p.m. only on Diwali.