(Reuters) - India has cut its windfall tax on petroleum crude to 8,400 Indian rupees ($100.66) a metric ton from 9,600 rupees with effect from May 1, the government said on Tuesday.

The tax, which is revised every fortnight, was left unchanged at zero for diesel and aviation turbine fuel.

The government had on April 16 raised the windfall tax on petroleum crude to 9,600 rupees a metric ton from 6,800 rupees.

($1 = 83.4500 Indian rupees)

(Reporting by Kanjyik Ghosh and Nikunj Ohri; Editing by Bernadette Baum)