The pope didn't telling the Chinese to double their population in how many years, nor was the message to make a shitload of kids. It was just don't fuck so much.
There's a pretty strict set of rules for having more than one child in China. Break them, and it's an automatic $12,000 USD fine, plus having to explain to the government why. The idea might have worked except for the cultural preference of male children. In the current coming-of-age generation, men outnumber women by about 16-1 so they're thinking of relaxing the restrictions. So much for that.
I have no explanation for India. My brother had to go there for a week last year, and he said it was truly terrifying.
I'm just hoping that approval of birth control by the Church might set the stage for a general shifting in attitudes; i.e., nobody HAS to squirt out a litter. One or two is perfectly acceptable. <_<