India, Sept. 15 -- Rescuers digging by hand into a flooded Nepalese hydropower tunnel are using rat-hole mining, a coal-extraction method India had banned in 2014, to reach six workers trapped underground since floods struck 20 days ago.

The joint India-Nepal team has cleared about 150 metres of the collapsed access tunnel at the Chilime project in Rasuwa district and was roughly 50 metres from the underground powerhouse where the workers were last seen. Excavators cleared the first stretch of boulders before the technique switched to manual burrowing through waterlogged debris, HT reported.

This is the second such rescue in as many years to reach for rat-hole mining after machinery seized up. At Uttarakhand's Silkyara tunnel in Novembe...