CHENNAI, April 18: The Tamil Nadu government on Friday announced 30 per cent power cut for industries and commercial establishments which used high tension power supply exceeding 150 KVA, from April 20. However, this would not apply to those coming under the `essential services' category.Power supply to agricultural pumpsets, which were presently provided for four hours in the day and six hours during night, would be extended by two hours at night.The restriction would be reviewed in June when the South-West monsoon begins and generation from the hydel power stations picks up. The minister said the power cut became inevitable after earlier measures failed to yield the desired results.