Oil and Natural Gas Corp
ONGC's overseas arm, ONGC Videsh, has a 25% stake in two joint-venture companies operating two oil blocks in South Sudan.
"The blocks are shut. So it made sense for us to evacuate our people as soon as possible," an ONGC Videsh official, who did not wish to be named, said on Tuesday.
The two blocks, where ONGC Videsh has invested about $700 million, had resumed production in April after staying shut since January 2012 due to political unrest.