The Competition Commission of India (CCI) said Google, the core unit of US firm Alphabet Inc, was abusing its dominance in online web search and online search advertising markets.
"Google was found to be indulging in practices of search bias and by doing so, it causes harm to its competitors as well as to users," the CCI said in a 190-page order.
"Google was leveraging its dominance in the market for online general web search, to strengthen its position in the market for online syndicate search services," the CCI said.
However, the CCI said it did not find any contravention in respect of Google's specialised search design, AdWords and online distribution agreements.
A Google spokesman said the company was reviewing the "narrow concerns" identified by the Commission and will assess its next steps.