Tenant Gave Notice In The Middle Of Lockdown

I have a property in Bangalore and it is being rented currently by three friends. Last week my tenant emailed and asked me to cut down the rent by 50% given their employee have told them that they will not get any appraisal and there won't be any bonuses this year. On that, I asked them if there is any salary cut to which they said no. I said that I will not give any discount on rent but I am happy to defer the rent for two months but without any waiver. On Apr 1st they sent me a notice that they will leave my premises in 30 days. My question to you is: 1) What if they cannot vacate the property by Apr 30 in case the lockdown is extended because of Covid? 2) If they continue to stay after April because of this lockdown can I legally ask them for rent for the extended period 3) If they don't pay me rent for the extended period what can I do in that scenario legally? I have a lease agreement signed which will be over by the end of August.