Tax on foreign incom

Hi,

If someone has NRI status for last financial year and in current financial year he is  returning to India in month of Aug.

Then, does he has to pay tax for foriegn income April-Aug or only on income after he reached India.

Same case if retrun date is between 01-Oct to 30Jan (if return is after 30Jan then no tax liability for current year)

Pls advice