I spent a couple of weeks in Manali in 1975 and enjoyed it very much. The best hash I smoked was bought from an American who said he'd rubbed it himself in Manikaran (Parvati valley). I'd never heard of Malana, but found this cautionary tale, which is quite a good read :

http://outside.away.com/outside/features/200501/malana-drug-trip_1.html