This is a major source of embarrassment for the world's largest democracy. India has no option but to address the genuine grievances of Kashmiris (Muslims and Pandits alike). So should Pakistan where the Kashmiris have been used as a pawn by various civil and military powerbrokers.
While Pakistan has no claim on being a democracy, given its struggles against military and civil dictatorships, India does claim to be the world's largest democracy. Incarcerating 20,000 without trial hurts India's standing among other democracies.
Kashmiris living in India and Pakistan have earned their right of self-determination after being suspended in a state of political vacuum since 1947. It is in India's and Pakistan's interest to resolve the issue of Kashmir by letting Kashmiris decide upon their own future. There is simply no other viable solution.
Kashmiris detained without trial in IndiaBBC News - Amnesty International criticises 'tough' Kashmir law