It's difficult to see in BW and in color at the same time or switch as opportunities come by. I've done it formy Last Cuba series and it worked but it killed my focus a bit.
Having shot exclusively kodachrome in 2009 and 2010, I can tell you it was a delight. I developedca sharp vision for colors and forms while BW called for moments instead.

For India, i think I'd go exclusively color. Look At McCurry's work.