I am not expert in Income Tax Act but I know about this query.
See Section 2(14) (iii) of the Income Tax Act. this is with effect from 1.4.14
[(iii) agricultural land in India, not being land situate-
(a) in any area which is comprised within the jurisdiction of a municipality (whether known as a municipality, municipal corporation, notified area committee, town area committee, town committee, or by any other name) or a cantonment board and which has a population of not less than ten thousand 47[***] ; or
48 [(b) in any area within the distance, measured aerially,-
(I) not being more than two kilometres, from the local limits of any municipality or cantonment board referred to in item (a) and which has a population of more than ten thousand but not exceeding one lakh; or
(II) not being more than six kilometres, from the local limits of any municipality or cantonment board referred to in item (a) and which has a population of more than one lakh but not exceeding ten lakh; or
(III) not being more than eight kilometres, from the local limits of any municipality or cantonment board referred to in item (a) and which has a population of more than ten lakh