ITR Filing Mandatory

Yes, Gross total income above basic exemption limit...

Yes it is mandatory to file return as your income before deductions of 80C 80D etc exceeds 2.50 lakhs basic limit.

No, basic exemption limit for ay 20-21 is Rs. 5 Lakhs

@ Sunita Manocha.,

Yes... Filing is mandatory if BEL is exceeding...

@ Harish Sharma.,

When / Where is BEL 5 lakhs....??

@ Harish
Basic exemption limit is 2.50 lakhs only.
However if total taxable income is less than 5 lakhs then whatever amount is tax liability ( maximum 12500/-) will be reduced as rebate from tax amount under section 87A

So for the purpose of return filing the basic limit is 2.50 lakhs.
And this limit of 2. 50 lakhs is determined on income before Deductions under 80C 80D. etc.

@ harish 5 lakhs exemption is only for senior citizens...

5 lakhs basic. exemption limit is only for VERY SENOIR CITIZENS (age above 80 years)

3 lakhs basic exemption for senior citizens (not 5 lakhs !!!!)

1. Any person whose income exceeds the basic exemption limit of Rs.2.5 lakhs without giving effect to Chapter VI-A deductions during the year needs to compulsorily file Return of Income. 
2. For the AY 2020-21, the basic exemption limit is still Rs. 2.5 lakhs and Rs. 5 lakhs is the limit for claiming rebate u/s 87A maximum of Rs. 12,500. 
3. So, if the income exceeds Rs. 2.5 lakhs but below Rs. 5 lakhs rebate u/s 87A can be availed by filing ROI. 
4. Basic exemption limit of Rs. 3 lakhs for senior citizens who are above 60 years of age and for super senior citizens who are above 80 years it is Rs. 5 lakhs. For the above assessee Rs. 3 lakhs and Rs. 5 lakhs will be considered for filling the ROI. 
Please correct me if the above solution has an alternative view.