New Delhi, India  (Photo: AP)

NEW DELHI (Xinhua) -- All schools in Delhi will be shut down on November 14 and 15 in the wake of extreme air pollution levels prevailing in the city, said the Environment Pollution (Prevention & Control) Authority (EPCA) on Wednesday.

Keeping in mind the hazardous exposure to children to air pollution, "we are constrained to take these steps because the current weather conditions are trapping pollutants and without any possibility of dispersion for the next two days, the condition of air quality is extremely unhealthy," said the EPCA, which has been mandated by the country's apex court the Supreme Court of India.

A letter written by EPCA Chairman Bhure Lal to the Government of National Capital Territory of Delhi, said that the concerned authorities will continue to make all efforts through the agencies to control local sources of pollution so that the situation can be mitigated as far as possible.

The EPCA also shut all hot mix plants and stone crushers till November 15, besides closing down all coal and other fuel based industries which have not shifted to natural gas or agro-residue in nearby towns like Faridabad, Gurugram, Ghaziabad, Noida, Greater Noida, Sonepat, Panipat, Bahadurgarh and Bhiwadi till November 15.

After respite for a few days, air quality in Delhi and surrounding areas once again turned to "Severe" category on Wednesday morning, even as the overall Air Quality Index (AQI) hovered around 500.

According to the "System of Air Quality Weather Forecasting and Research (SAFAR)", an AQI between 0-50 is termed as "Good", 50-100 as "Satisfactory", 100-200 is considered as "Moderate", 200-300 as "Poor", 300-400 as "Very Poor", and 400-500 is described as "Severe", and above 500 is categorised as "Emergency".

Some areas near Delhi like Gurugram in neighbouring state of Haryana witnessed an AQI above 500, posing an "Emergency" situation.

Noida, a city in neighbouring state of Uttar Pradesh, too continues to record an AQI of above 500.

According to media reports, the prevailing air quality conditions in and around the Indian capital may lead to serious health problems like respiratory diseases and even heart ailments.

The main reason attributed to the deteriorated air quality is the burning of crop residues by farmers in northern state of Punjab and Haryana