NEW DELHI: One of the most popular mobile application, SMS, may soon become cheaper. According to a business daily, Telecom Regulatory Authority of India (TRAI) has asked mobile operators to reduce SMS charges voluntarily. According to the report, unlike voice traffic, the cost component in SMS is very low -- around 2 paise, however, most service providers either charge higher tariff for an SMS or almost comparable. Quoting sources, the report says that TRAI has held negotiations with Cellular Operators Association of India (COAI), the apex body of GSM mobile operators, to convince them to slash SMS tariff, falling which it may have to intervene through regulation. The move is being stiffly opposed by the service providers, as SMS makes for almost 50 per cent of their revenue. Already battling lower Average Revenue Per User (ARPU), service providers argue that revenue from value added services are critical to their survival. Incidentally, this is not the first time that TRAI has urged service providers to reduce the SMS cost. The regulatory body had asked operators to slash SMS rates two years ago too.