After the introduction of Rule 36(4), there are restrictions on availment of ITC where supplier has not filed the GSTR-1 of the period/month to which the invoice relates.
w.e.f. 01.01.2020, you can claim ITC as follows:
A) Total eligible ITC as per books of accounts
B) Eligible ITC as per GSTR-2A (i.e. the ITC of those invoices which are getting reflected)
C) Provisional Credit: 10% of B (before 01.01.20 20%)
D) Total eligible ITC that can be claimed: B+C
(Note: If, D>A, then C will be reduced to that extent since D cannot exceed A)
You can claim the balance ITC in the succeeding months after the pending invoices start reflecting in your GSTR-2A, as and when filed by your supplier.