India is facing a situation today when a tube light has suddenly come on and it has been realised that nonlethal weapons may be needed for crowd control. It just does not do to scale up from lathis to bullets - a crowd control tactic that has come down to us from the Brits during the independence movement. The rest of the world has moved on. We have not.
Two factors play in my mind. One is the statement that non lethal weapons will have to be urgently introduced into Kashmir. And the second was the question by Hari Nair in the LCH thread about ideas for non lethal weapons.
Of course Google uncle will give you a list. First - "non lethal" is a relative term. A few will get killed over time.
I know that Indian police use tear gas and water cannon. Tear gas probably is dependent on wind direction and perhaps it tends to get thrown back. Perhaps water cannot is too short ranged and ineffective for violet crowds armed with stones. Mind you this is my speculation and anyone who knows better - please give gyan.
The Brits introduced Rubber bullets into Northern Ireland. I am not sure how non lethal those will be. They also used plastic bullets.
There was a news item about a Bhoot Jalokia grenade. I don't know if it was merely an idea, but apparently US forces have used chilli pellets. Again I have no idea of efficacy. This has been criticised by human rights groups as "torture"

Apart from this there are reports of bean bag pellets, sound waves that incapacitate people, and the recently linked video on BR of microwaves that make it too hot for a person to stand under its radiation. Was this used in Afghanistan and then withdrawn?
Just to get the brain cells whirring and add some color - I will link a photo of a water cannon made by DRDO in use: (I hope everyone can see the image. I can)