New Delhi, Aug. 19 -- The Indian stock market extended its rally on Tuesday, marking the fourth straight session of gains. The Sensex rose more than 400 points, while the Nifty 50 crossed the 25,000 level in intraday trade, supported by easing geopolitical tensions and strong domestic developments.

Optimism improved as global markets advanced on hopes of progress towards resolving the Russia-Ukraine war. Sentiment was buoyed by diplomatic efforts, including US President Donald Trump's meetings with Ukrainian President Volodymyr Zelensky, European leaders, and earlier discussions with Russian President Vladimir Putin.

On the domestic front, Prime Minister Narendra Modi's announcement of a significant Goods and Services Tax (GST) reform f...