My two bits of lead...
Here, in North India, I've noticed that it's the river that decides what works.
1. On the River Ramganga, running into Corbett National Park, you'll get great action with Krocadiles, spinners, minnow spoons, Hog backs, chilwa & aata. However, I've never known of a good sized mahseer taking a plug.
2. On the River Ganga, say the Bayansghat to Rishikesh stretch, you'll catch mahseer on spoon, spinners and plug. Chilwa & aata also work especially in coloured water.
3. On the River Kali, on the Indo-Nepal border, you would only use a plug. The exception I know of being a 40pounder taken on a 6inch brass spoon at last-light by a gent named Chris Oldsfield and a nut-cases like me experimenting with home-made spoons. The Kali also produces fish on live bait & aata.
My favourite plugs are the Yo-Zuri's & Rapala 14cm & I use 'floating' and 'deep-diving' depending on the water/run I'm fishing. Most of my bigger fish have been on the Rapala Blue Mullet. Yes, I change my hooks to 3x but I've even had one of those chewed up, one tine almost straightned and spat out.
You tend to get the big fish to strike when you fish deep - with a very slow retrive, bouncing the plug along the river bed - at the risk of a snag of course - but that big hit is worth the trouble of using an 'otter' where possible to un-do a snag or mastering the technique of scraping the river bed or even losing a couple of plugs.
The Rapala's 18cm 3/4 jointed is a killer but I dont have one yet. I think its called the "Sliver" in the cat.
Tight lines people,
a.k.a. Big Mahseer