The Pakistani government on Sunday announced that all primary schools in northeastern Lahore, the country's second-largest city, will remain closed for a week as air quality worsened to a record level due to thick smog, according to Anadolu Agency.

The government of northeastern Punjab province, for which Lahore serves as the capital, took the decision to avoid exposing millions of children to a thick pall of smog that has wreathed the city over the past several days.

Lahore will close primary schools for a week over record pollution, government authorities said, to avoid exposing millions of children to smog several times above levels deemed dangerous.

All classes "for children up to the age of 10, public, private & special education … shall remain closed for one week" from Monday until Saturday, said a city government notification.

In an unprecedented development, the air quality, which measures a range of pollutants, was recorded above 1,000 on Sunday -- well above the level of 300 considered “dangerous” -- according to data from IQAir, an air quality technology firm.

Authorities will assess the situation again next Saturday to determine whether to extend the school closure, the notification added.

The move came days after the Punjab government ordered all special education schools in Lahore to send students with conditions susceptible to poor air on a three-month leave.

Known as Pakistan's cultural hub, Lahore -- home to over 14 million people -- regularly battles with cancer-causing mix of fog and pollutants every year, primarily blamed on burning of stubble by farmers in neighboring India to clear their fields for ploughing, and industrial and vehicular emissions.

The government has banned several pollution-causing activities across the province, including burning any type of crop residue, solid waste, tires, rubber, and plastics, as well as vehicles emitting visible smoke and pollutants falling into inadmissible limits.

Use of facemask has also been recommended to avoid smog effects but only a few are following the advice.

The early strike by the smog this year also prompted Punjab Chief Minister Maryam Nawaz to seek coordination with the neighboring Indian Punjab, which, along with the national capital Delhi, has long been facing the same problem.