Question

is it important to increase the area under irrigation why

Answer 1

to increase the rice cultivation so it had become third largest exporter of rice in India

Answer 2

As for India, agriculture is the primary activity here. And for agriculture water is  part and parcel aspect. So it is very important to increase the area under irrigation as without water nothing can be done. As we know, India is summer-climatic country so proper irrigation is must for agriculture. Some parts of India get less rainfall that can affect their crop growth. Due to less rainfall production of crops will be questioned. 
Therefore, it is the call of the hour for us to increase the area under irrigation.