The smoggy weather conditions, which were prevailing in Punjab province were beyond the PIA's control, so they had to either delay or cancel the flights, the airline spokesperson was quoted as saying on Wednesday.
The affected areas included Multan, Faisalabad, Lahore, Bahawalpur, Sialkot and Rahim Yar Khan, Xinhua news agency reported.
The PIA said that 83 flights were rescheduled, 82 re-routed, 17 diverted and 159 flights were cancelled due to poor visibility.
Another 200 flights were delayed to ensure the security requirements in the bad weather, it said.
The plains of Punjab, remained engulfed by a thick smog blanket in the first two weeks of November, but scattered rains, which started in the country on Tuesday, washed away the smog from most of the areas.
Pakistani Met officials told Xinhua earlier this week that the province would get a respite from smog following the downpour, but fog will continue in the area.