Over 70 domestic and international flights were delayed due to heavy smog at Lahore's Allama Iqbal International Airport on Friday for the fourth day running, leaving thousands of passengers and their relatives inconvenienced, DawnNews reported.

Flights are expected to continue being delayed over the next few days, keeping in view weather conditions.

Passengers and their relatives began protesting at the airport against the delays. Protesters complained that their concerns were not being heard by the airport's administration.

The problems caused have also been exacerbated as airlines lack channels of communication with each other, the protesters told DawnNews.

They added that officials tell passengers flights will arrive and depart on time, but when they reach the airport they are informed that their flights have been delayed.

"We don't know where to take our problems," a protester told DawnNews.

Since late October, large swathes of Punjab have remained engulfed in harmful smog.

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Air quality indicators show high levels of particulate matter, with breathing conditions in urban areas ranging from highly unhealthy to very hazardous.

Readings from Lahore taken in the last week of October indicate the level of carbon monoxide at 21.29 milligram per metre (mpm) on Mall Road, 17.52 in Mohlanwal, and 6.94 in Gulberg’s Liberty Market. The maximum permissible limit under World Health Organization guidelines is 5 mpm.

This year, public outcry over the issue has been far more amplified. Citizens of Lahore are using social media to pressurise provincial and local government bodies.

As a whole, there is considerable urgency on part of the affected population as they try to get the government to deal with the issue as a public health emergency.