In its daily bulletin on the blowout incident, ONGC said it has achieved a "critical milestone" in its ongoing well control operations at the site.

"With precision and coordination, the extra-long boom crane and a 40-ton crane successfully worked together to remove the 42 tubing stands from the derrick of the rig, clearing the path for the safe removal of the rig base from the wellhead," it added.

The blowout took place on June 12 at Well No RDS 147A of Rig No SKP 135 of Rudrasagar oil field of Oil and Natural Gas Corporation at Barichuk of Bhatiapar. A private firm, SK Petro Services, was operating the well on behalf of the state-run Maharatna company.

The statement said that following the removal of the rig base, the next phase of operations involves dismantling the existing Blowout Preventer , followed by the installation of the capping stack.

"During this sequence, a temporary increase in gas discharge is anticipated. ONGC assures that the gas is nontoxic and the volume is significantly reduced, presenting no risk to inhabitants residing beyond a 500-metre radius," it added.

The company also said that it continues to make concerted efforts to control the unabated gas discharge from the well.

"Water blanketing operations continue as part of ONGC's layered safety strategy, while both ONGC and its technical partner CUDD remain fully focused on executing the well control operations in a carefully calibrated and safe manner," it added.

Water is being pumped continuously at high pressure from the Dikhow river, which is flowing near the rig. However, the rising waters in the river have introduced additional logistical challenges.

"In response, the teams are proactively relocating high-capacity pumps to maintain uninterrupted support to ongoing safety systems," ONGC said.

It further said that ambient air quality continues to be rigorously monitored with all key parameters well within permissible limits, while medical and relief camps also remain operational to ensure the well-being of personnel and nearby communities.

"ONGC reiterates its commitment to operational excellence, environmental responsibility and community safety, and continues to work with determination to bring this complex operation to a safe and successful conclusion," the statement said.

Three blowout experts from the US reached the site on June 20 and are actively engaged in the massive exercise to control the well.

Last week, Assam Chief Minister Himanta Biswa Sarma had urged Union Petroleum and Natural Gas Minister Hardeep S Puri to ask the energy major to ramp up their effort to control the blowout in a 'mission mode'.

Sarma had also written to Puri, saying that locals believe there has been "inadequate urgency and seriousness in ONGC's response" while trying to control the well.

The prolonged nature of the incident is causing considerable distress in the surrounding villages as already more than 330 families have been evacuated from their homes and are being supported with basic relief and safety measures at a camp set up in nearby Bangaon.

The Assam government has announced financial aid of ₹25,000 each to about 350 families affected by the blowout.

An official of ONGC had earlier said that it was an old crude well without production and a perforation job was going on for zone transfer at the time of the blowout.

"It is a kind of servicing of the well. The production was supposed to start from a new zone after the perforation job. At the time of the incident, the logging perforation operation was going on. Suddenly gas started coming out in an uncontrolled manner immediately after the perforation, leading to the blowout," he had added.