Private limited - number of directors are less than required

You can appoint another director and run the company.  Even a single director can form quorum for the meeting for this purpose.  Section 174(2) of Companies Act 2013 reads as under:

"The continuing directors may act notwithstanding any vacancy in the Board; but, if and so long as their number is reduced below the quorum fixed by the Act for a meeting of the Board, the continuing directors or director may act for the purpose of increasing the number of directors to that fixed for the quorum, or of summoning a general meeting of the company and for no other purpose."