Vietnam-based mobile operators Viettel, MobiFone, and Vinaphone have increased their 3G tariffs by about 40 per cent, after receiving the approval from the country’s Ministry of Information and Communications. This is the second instance of a tariff hike by operators that state that the resultant increase in revenue can help them to upgrade and expand their networks. Earlier this year, the operators had increased the cost of their unlimited 3G mobile data plans by 25 per cent.