NEW DELHI: The Delhi government on Tuesday announced that primary schools would be closed on Wednesday in view of deteriorating air pollution conditions in the city.

Moreover, all schools have been asked to stop outdoor activities, including morning assemblies, Deputy Chief Minister Manish Sisodia said.

"Primary schools in Delhi, including private ones, will remain closed tomorrow. We are monitoring the situation on an hourly basis and a further decision on the measures will be taken on Thursday," he told reporters.

The government has also issued a health advisory for high risk people, including children, the elderly and those suffering from asthma and heart ailments.

"We appeal to the people of Delhi to avoid morning and evening walks," he said.

The situation following the alarming pollution levels in the city was reviewed by Delhi Chief Minister Arvind Kejriwal at a meeting with officials, including those from Health and Environment department.

The combination of smoke from stubble burning in Punjab and Haryana and moisture turned Delhi into a "gas chamber" today, prompting the Supreme Court mandated green body EPCA to announce a series of preventive measures, including a four- fold hike in parking fees and slashing of Metro fares in off- peak hours.

The smog brought down visibility levels, affecting flight and train operations. The heavy air permeated living rooms and even underground Metro stations.

The air quality index was in the 'severe' category -- with a score of 448 in a scale of 500 -- category for the second time this year.

Earlier, Diwali fireworks had triggered peak pollution levels on October 20.