Prime Minister Narendra Modi’s Bharatiya Janata Party suffered an electoral setback in a key by-election in India’s Bihar state on Monday, a first since nationwide student protests forced him to replace his education minister.

Political strategist-turned-politician Prashant Kishor, contesting his first election as founder of the Jan Suraaj Party, defeated BJP candidate Neeraj Kumar, winning the Bankipur assembly seat by over 19,000 votes, according to the Election Commission of India.

The Bankipur seat has voted for the BJP four consecutive terms since 2010, and was most recently held by Nitin Nabin, the party’s president. The election was the first political test for Modi since mass student protests two weeks ago, raising questions over whether the party can retain its support among the country’s young population.