What is the time limit for making the assessment under section 147 i.e. income escaping assessment?
As per section 153, the time limit for making assessment under section 147 is:-

Within 9 months from the end of the financial year in which the notice under section 148 was served (if notice is served before 01-04-2019).
12 months from the end of the financial year in which notice under section 148 is served (if notice is served on or after 01-04-2019).
Note: If reference is made to TPO, the period available for assessment shall be extended by 12 months