Wearing masks has again been made mandatory for domestic flights with immediate effect amid a rise in Covid-19 cases in the country, according to a notification from the Civil Aviation Authority (CAA).

The CAA directed all concerned quarters to ensure compliance with the new order, but added that the other Covid-19 guidelines on domestic air travel remained unchanged.

Earlier today, Pakistan reported more than 400 coronavirus cases for a second consecutive day as Karachi's positivity rate was recorded at 21.71 per cent — the highest in the country.

Data released by the National Institute of Health (NIH) showed that 406 Covid-19 cases were reported across the country during the last 24 hours. A day earlier, 435 cases were reported — the highest number since March 22.

According to the NIH, 14,437 tests were conducted during the last 24 hours. The positivity rate was recorded as 2.81pc while two more deaths were also reported. In addition, 94 patients were in critical care, up from 87 a day prior.

Talking to Dawn, University of Health Sciences Vice Chancellor Dr Javed Akram had said the virus was behaving like a "roller coaster".

“The country will face similar situations for a few years,” Dr Akram said, suggesting that restrictions should be imposed once again as they would not only bring cases down but also help overcome the prevailing energy crisis.

Dr Javed Akram, who is a member of the Scientific Task Force on Covid-19, said the immunity level among people was decreasing and the efficacy of vaccines, which was once 95pc, had fallen to around 80-85pc as the virus was continuously mutating.

Vaccines are losing efficacy but even then they were the only shield against Covid-19, Dr Akram said, adding that people should go for vaccination and those who were already immunised should get booster shots. He said Moderna vaccine supply was short but its consignment had arrived two days ago.

“People should take precautionary measures and strictly adhere to SOPs (standard operating procedures),” he said, adding that Pakistan was in the grip of a severe energy crisis so if restrictions were imposed, the country would not only be able to control the pandemic but also overcome the energy crisis.