The Oil and  Gas Regulatory Authority (OGRA) Tuesday issued notification of the increase in gas tariff.According to the notification, the prices gas have been raised by 31 to 121 percent for the domestic users consuming more than 200 cubic meters of gas.OGRA increased the domestic users' categories from 5 to 7. First three categories are exempted from the rise in gas tariff while the fourth and fifth categories will pay 31 percent more on gas usage.The rates have been increased by 120 per cent on the last two luxury categories.