Rules, fees, permits
In the 90's you could trek in the Garhwal with a minimum of formality, provided you stayed away from the Inner Line. For me, that was one of the main reasons for choosing the Garhwal rather than, say, Nepal. But that was then and this is now.
The photo, posted on the IndiaMike Forum in July 2011, shows the fees applicable around Gangotri last season . It looks as if the cost is Rs 150 for Indians and Rs 600 for foreigners for a two day trek, with a further charge of Rs 50/250 for each additional day. Plus another Rs 500/1500 (which may or may not actually be collected) for photography.
In other areas, too, it seems that permits and fees apply and there may also be a requirement to trek with a guide.
In the area around the Kuari Pass, in the south-west corner of the Nanda Devi Massif, regulations were in the 90's either absent or unenforced. At least that was my experience. But some trekking routes in this area fall wholly or partly within the buffer zone of the Nanda Devi Biosphere Reserve. It seems that a permit system applies to these routes and is currently being enforced fairly energetically by the Forest Department.
The fees reportedly charged in 2007 were moderate (Rs 60 per adult trekker, rising to Rs 100 per adult trekker for periods longer than seven days; Rs. 50 per night for a small/medium tent; plus a fee for porters, guides and mules). But it appears that the employment of a guide may be mandatory. If that's the case it's a very restrictive policy and may well increase the ecological burden on the area by encouraging trekking caravans.
Trekking rules in the Garhwal are complex and not well publicised. The best way to get reliable information seems to be to scour the IndiaMike Trekking and Mountaineering Forum.
But even if you're clued up and kitted out with a full portfolio of passport photos and a well-stuffed wallet, is this really any fun? Do you want to fill in a form detailing where you'll be camping each night? Do you want to have a guide and porters imposed upon you? Is it what you go to the Himalaya for?