India opened the scoring against the run of play in the 19th minute through Akashdeep Singh's strike, courtesy a lapse in concentration from Oman defence.
Talwinder Singh doubled India's lead in the 30th minute with another field goal after he was nicely set up by Prabhdeep Singh.
After the change of ends, the Indians found it difficult to breach the Omanese defence till the 62nd minute when Amit Rohidas converted a penalty corner to make the scoreline 3-0.
India had earlier lost 0-2 and 1-2 to China and hosts Japan in their opening two matches in the tournament.