NEW DELHI—More than 1,000 Indian Muslim scholars and religious leaders have jointly condemned Islamic State in an effort to counter the militant group’s drive to recruit young men and women in a country that is home to the world’s second-largest Muslim population.

India’s Home Ministry says it knows of 17 Indians who have joined Islamic State, a strikingly low figure compared with the hundreds of Muslims from Europe and Australia who have joined the organization to fight in Iraq and Syria.

Indian...