Over 500 rescue personnel from state, disaster and defence forces are racing against time to rescue the 34 workers — and there could be more — believed trapped inside a 1.6-km-long debris-filled tunnel of the Tapovan-Vishnugad hydel project in Uttarakhand’s Chamoli district. The flooded Dhauliganga is the river on which the project was being built. The rescue effort on Monday — with two National Disaster Response Force teams, over 300 Indo-Tibetan Border Police personnel, a Sashastra Seema Bal team and over 120 from the Army — was entirely channelised towards that one tunnel. The 12 men in the other tunnel of the project had been rescued on Sunday.