The order comes a day after Pakistan's biggest city, Karachi, reported that its Covid-19 positivity ratio, or the rate of positive cases out of all tests conducted, rose to 21% compared with a national rate of 2.8%.
"With immediate effect, mask wearing will be mandatory onboard domestic flights,” the Pakistan Civil Aviation Authority (PCAA) said in the statement late on Sunday.
Pakistan has had very few Covid-19 cases over recent months and had done away with almost all precautions.
But over the past 24 hours, the national Covid-19 positivity ratio had risen to 2.85% with 382 positive cases and two deaths, according to data released on Monday by the National Institute of Health, Islamabad (NIH).
A month ago, the positivity ratio was 0.54% with 79 positive cases and no deaths. According to the NIH, 85% of eligible Pakistanis have been fully vaccinated against Covid-19.
Pakistan disbanded the National Command and Operations Center, which was overseeing the Covid-19 response, on March 31 as infections fell to the lowest since the outbreak began in 2020.
By Syed Raza Hassan
(Reporting by Syed Raza Hassan; Editing by Robert Birsel)

A Pakistani man receives a dose of a Covid-19 vaccine as the government achieves the milestone to fully vaccinate 100 million citizens in Hyderabad, Pakistan 07 March 2022. EPA-EFE/NADEEM KHAWAR