By 0525 GMT, the blue-chip NSE Nifty 50 index had fallen 0.77% to 17,761.30, while the benchmark S&P BSE Sensex had lost 0.65% to 59,615.45.

Both the indexes have struggled this week, hurt a combination of rising inflation worries globally, valuation concerns, and an end to the domestic September-quarter earnings season.

"Because of the extraordinary monetary accommodation provided by global central banks... the valuations of many businesses (have become astronomical)," said Ajay Bodke, an independent market analyst.

Broader global stock markets also slipped as rising inflation worries clouded the outlook for interest rates and growth. [MKTS/GLOB]

In Mumbai trading, Paytm's shares tanked as much as 26.2% in their stock market debut, whose initial public offering of 183 billion rupees is India's biggest.

The Nifty Auto Index fell 2.12% and was on track to snap two straight sessions of gains. Tata Motors lost 4.2% to be the top percentage loser on the Nifty 50.

The Nifty IT index was down 1.66% and was set to break a four-day winning streak. HCL Technologies fell 2.8%.

Sapphire Foods India, a domestic franchisee of KFC and Pizza Hut operator Yum Brands, gained 4.1% in its market debut.

Shares of oil-to-metals conglomerate Vedanta fell 5.6%. The company on Wednesday said it had constituted a board committee to evaluate strategic measures.

(Reporting by Anuron Kumar Mitra in Bengaluru; editing by Uttaresh.V)

By Anuron Kumar Mitra