Gravitational acceleration at the surface of earth varies with latitude (North-South position). This is due to 1) the outward centrifugal force produced by Earth's rotation, and 2) the equatorial bulge (itself caused by Earth's rotation). Both effects cause the gravitational acceleration to decrease away from the poles. The net effect is a gravitational acceleration of about $9.832$ $m/s^2$ at the poles, and about $9.780$ $m/s^2$ (0.5 % lower) at the equator.
For any sea level position on Earth (your city, Jamnagar, at 17 m elevation can indeed be considered to be roughly at sea level), we can estimate the gravitational acceleration $g$ at any latitude $\phi$ using Helmert's equation:
$$g(\phi ) = g_0 (1 + 0.0053024 sin^2 \phi - 0.0000058 sin^2 2\phi) $$
where $g_0 = 9.780327 m/s^2$ denotes the gravitational acceleration at the equator.
Local variations in Earth's topography and geology cause local deviations from the above formula. Such local variations are known as gravitational anomalies. To include these would go way beyond the intentions of the exercise.