Asian shares traded in the negative territory after polls in the UK threw up a hung Parliament and markets await the results of the first round of France's parliamentary elections.
The 30-share index plunged by 155.91 points, or 0.49 per cent, to 31,106.15.
The gauge had gained 48.70 points in the previous session on Friday.
Sectoral indices such as technology, IT, capital goods, bank, PSU, power, auto, oil and gas tripped, falling by up to 0.62 per cent. Major IT players felt the heat as Wipro, TCS and Infosys slid by up to 2.08 per cent.
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Profit-booking by participants paced up ahead of key macro data - index of industrial production (IIP) for April and consumer price index-based inflation for May are slated for release after market hours today.
A depreciating rupee against the dollar weighed, traders said.
While Japan's Nikkei was down 0.36 per cent, Hong Kong's Hang Seng shed 1.02 per cent in early trade today. China's main Shanghai Composite was also down by 0.24 per cent.