More than 10 million people in India's capital, Delhi, are without water after protesters sabotaged a key canal which supplies much of the city.
The army took control of the Munak canal after Jat community protesters, angry at caste job quotas, seized it.
Keshav Chandra, head of Delhi's water board, told the BBC it would take "three to four days" before normal supplies resumed to affected areas.
All Delhi's schools have been closed because of the water crisis.
Sixteen people have been killed and hundreds hurt in three days of riots.
Sixteen million people live in Delhi, and around three-fifths of the city's water is supplied by the canal, which runs through the neighbouring state of Haryana.