Question

how can we convert India's population into an asset rather the liability

Answer 1

It will be an asset for India for a number of reasons which I will describe in a short while. But before that let us agree on some fundamental problems that will arise because of the population growth: 

Higher population means extra burden on state to manage its resources well. (Obvious point eh?)In an already chaotic country like India, it is hard to imagine how it would look like in the next 30-40 years. Yes, the infrastructure would be a huge concern.If we are not able to provide equal opportunities and jobs to all the sections, the consequences would be highly dangerous. We have already seen the emergence of Naxalites and how they have affected us in the recent past.
Now let's talk about what we can do and how we can be benefited from this huge population. 

First of all, more people mean more (potential) consumers. In a growing market like India where the middle class has powerfully grown in the recent decades, there is a vast market for everyone. Yes, I mean everyone. From a five star hotel to Rs 2 biscuit pack, every business will find millions of customers. And who would not want that kind of market? In a world where even facebook likes will fetch you money, having the adequate human resource is a powerful tool.