Teaching English per se could be tough, as there are tons and tons of native folks in India teaching English, for very small sums of money.
The real money in India is in the wonderfully termed "accent neutralization" classes that all of the call center companies need. I talked to a few people teaching in that capacity during a recent trip to India and they said the pay and condition were good.
The downside was the hours. Many of the shifts were aligned to US day time which is India night time. It made for an interesting lifestyle.