Residential Status of an Individual

6. For the purposes of this Act,—

 (1) An individual is said to be resident in India in any previous year, if he—

 (a) is in India in that year for a period or periods amounting in all to one hundred and eighty-two days or more ; or

 (c) having within the four years preceding that year been in India for a period or periods amounting in all to three hundred and sixty-five days or more, is in India for a period or periods amounting in all to sixty days or more in that year.

Explanation. 1—In the case of an individual,—

 (a) being a citizen of India, who leaves India in any previous year as a member of the crew of an Indian ship as defined in clause (18) of section 3 of the Merchant Shipping Act, 1958 (44 of 1958), or for the purposes of employment outside India, the provisions of sub-clause (c) shall apply in relation to that year as if for the words "sixty days", occurring therein, the words "one hundred and eighty-two days" had been substituted ;

 (b) being a citizen of India, or a person of Indian origin within the meaning of Explanation to clause (e) of section 115C, who, being outside India, comes on a visit to India in any previous year, the provisions of sub-clause (c) shall apply in relation to that year as if for the words "sixty days", occurring therein, the words "one hundred and eighty-two days" had been substituted.

Explanation 2.—For the purposes of this clause, in the case of an individual, being a citizen of India and a member of the crew of a foreign bound ship leaving India, the period or periods of stay in India shall, in respect of such voyage, be determined in the manner and subject to such conditions as may be prescribed.

 (6) A person is said to be "not ordinarily resident" in India in any previous year if such person is—

(a) an individual who has been a non-resident in India in nine out of the ten previous years preceding that year, or has during the seven previous years preceding that year been in India for a period of, or periods amounting in all to, seven hundred and twenty-nine days or less; or

(b) a Hindu undivided family whose manager has been a non-resident in India in nine out of the ten previous years preceding that year, or has during the seven previous years preceding that year been in India for a period of, or periods amounting in all to, seven hundred and twenty-nine days or less.

Ref: https://www.incometaxindia.gov.in