Dhaka Metropolitan Transport Committee has stopped renewing route permits of buses and minibuses over 15 years old, as the communications ministry has decided to impose restrictions on such vehicles in the city. According to the decision, the bus owners should withdraw such buses from Dhaka and can replace their old buses with CNG-run 52-seater buses, an official handout said yesterday. The bus and minibus owners can also operate their old vehicles outside Dhaka and Chittagong cities, it added. Before operating the old buses and minibuses in areas outside the two metropolitan cities, the transport owners should collect transfer certificates from the registration authorities in Dhaka and take permission from the authorities concerned in the areas where the vehicles will ply.