A team of Indian navy divers has been deployed in a bid to rescue 15 workers trapped inside a flooded coal mine.
The men had entered the illegal pit, known as a "rat hole", in the north-eastern state of Meghalaya on 13 December, and were cut off when floodwater from a nearby river poured in.
Emergency workers equipped with high-power pumps have arrived at the scene.
It is not yet clear whether the miners are still alive.
India's NDTV reports that divers have recovered nothing but three helmets so far.
Officials hope the men may have found an air pocket in the main mineshaft.
"Only God's grace and some miracle can help them to be alive," Kyrmen Shylla, Meghalaya's disaster management minister, told Reuters on Wednesday.
Earlier rescue efforts by India's National Disaster Response Force (NDRF) and State Disaster Response Force (SDRF) were hampered by a lack of equipment. Initially, only two low-power pumps were on hand to drain the water.
The 112m (370ft)-deep coal mine where the workers are trapped lies in the remote East Jaintia Hills district.
Rat-hole mining involves digging pits into the ground to create a narrow hole to find coal, and is dangerous for those involved. Workers, including children, descend into the mines using bamboo ladders and accidents are common.
The practice was banned in 2014, but mine owners have challenged the ruling in India's Supreme Court.
Most of Meghalaya's illegal miners are migrant labourers who come from neighbouring states to earn money.