Reliance Industries and its partner BP plc's KG-D6 gas fields and gas discovery area NEC-25 are among 14 oil and gas blocks that have been declared "No-Go" areas by the Defence Ministry, barring any exploration or production activity.
Ministry of Defence has either withdrawn or withheld clearances for 47 oil and gas blocks.
Of these, 14 have been classified as "No-Go" areas, sources privy to the development said.
RIL-BP's KG-DWN-98/3 or KG-D6 block has been declared as "No-Go" as it overlaps with a proposed Naval base.
KG-D6, which was awarded to RIL in 2000 by the Cabinet after clearance from all ministries concerned, had been producing oil since September 2008 and gas from April 1, 2009.
RIL-BP's Mahanadi basin block NEC-OSN-97/2 (NEC-25) where sizable gas discoveries have been made, too has been classified as "No-Go" area as it is close to missile launching range/air force exercise area.
Sources said the other 12 "No-Go" blocks are with state- owned ONGC, Cairn India and Australia's BHP Billiton and reasons cited for withdrawing clearance including being close to missile launching range, overlapping with proposed Naval base, with the Naval firing range and Air Force exercise area.
Companies like RIL have already invested $15 billion since 2000 and the Ministry of Defence has now withdrawn or withheld clearance to them.
Sources said the newly constituted Cabinet Committee on Investment (CCI) is likely to consider this week giving clearance to 47 oil and gas blocks where the Defence Ministry has either withdrawn clearances or put stringent conditions.
Finance Minister P Chidambaram had last week indicated that the CCI would for the first time meet before the end of this month in which clearances to oil and gas blocks would be considered.