Agartala, October 10 (IANS) Despite Tripura being the toughest zone for gas exploration in the world, the success ratio here is the best, a top ONGC official said. The Oil and Natural Gas Corporation has drilled 225 wells in Tripura so far, of which 116 were found to be gas-bearing. "Due to high pressure of gas and unusual formation beneath the soil, Tripura is the toughest zone for drilling and exploration of gas in the world. However, success ratio is 1:2 in the state against the world success ratio of 1:5," ONGC's Executive Director Gautam Kumar Singha Roy told media persons here on Monday night. "The sub-surface zone is also very intricate." He said the company would start exploration works in the Tichna area after it gets forest and environment clearance from the central government within the next six months. The Maharatna company has, for the last 12 years, not been able to proceed with its exploration work in the region due to the lack of environmental clearance as it falls under the Tichna (Trishna) Bison National Park and Wildlife Sanctuary. The ONGC has, since 1962, established around 41 billion cubic metre (BCM) of recoverable gas reserves in Tripura's 11 gas fields. Roy said the ONGC had to spend Rs 16 lakh per day for drilling of gas in Tripura against Rs 4.5 crore in the deep sea areas. "The ONGC has a plan to spend Rs 1,000 crore during the current financial year in Tripura against Rs 662 crore in the last financial year (2016-17)." The ONGC earlier planned to set up a Rs 5,000 crore fertiliser plant in Tripura in association with the state government and Rajasthan-based firm, Chambal Fertilisers and Chemicals Ltd. "The fate of the proposed fertiliser plant is not bright as sufficient natural gas is yet to be found in the Khubal area. At least 25 gas producing wells are required for such a big fertiliser plant. ONGC has so far drilled eight wells and gas has been found in only onel," the official added. The firm had commissioned its first commercial gas-based power project in India, located in Palatana, 60 km south of Agartala, and run by the ONGC Tripura Power Co (OTPC). The 726 MW capacity combined cycle project has been supplying electricity to the seven northeastern states and 160 MW to Bangladesh.