Can I discontinue PPF contributions in the middle of the 15 years?

I am holding PPF account for last 6 years and depositing 50000/- every year. Now due to some personal requirement, I am unable to continue the same amount, I have two queries on it -
1- Can I discontinue PPF contributions in the middle of the 15 years?
2- Or do I need to pay Min 500/- this year also?

Why you want to discontinue, just deposit min 500. Or take a loan from the PPF account and deposit 500 in it and keep remaining with you.