How can we regularize npa loan

No other option, but to sit with Bank officers and explain the situation.

Secondly, you will have to accept that you have defaulted the repayment terms as signed in agreement, though may not be in your hands.

Thirdly, the credit rating will change as soon as you start repaying the debt.

Dear sir, 

Thanks for your response, I will negotiate with the bank as you said. Hope they give me option to start paying through EMI. 

Yes, they will be happy to receive back their funds, and may even reduce the penalties and or interest payment.