Iran’s transportation minister has announced new guidelines for establishing airlines, including an import ban on airplanes more than 15 years old.

The Mehr News Agency reports that the minister said on Saturday December 20 that in view of three decades of sanctions on Iran’s aviation industry, “we need to focus on our responsibility in this field.”

Iran has 18 airlines, and Abbas Akhoondi said the average age of their airplanes is 22 and a half years. He added that airlines that use leased airplanes will no longer be given flight permits.

The new guidelines come after the crash of an Antonov airplane killed 30 passengers and crew, which prompted President Rohani to order an immediate ban on flying the Ukrainian-built aircraft.