Over the years, rooftop solar photovoltaic has been considered as a practical and climate conscious approach for building design, development, and comfortable living. In this paper, Carbon Credit (CC) of a rooftop grid-connected solar PV system installed in National Capital Region (New Delhi, India) is investigated for viability purposes for Indian composite climate. The system under consideration is of 330 kWp capacity; it consists of several subarrays and we have carried out experimental measurement of two units (subarrays) of identically rated (20kWp each) component characteristics to investigate the differences between rated and the actual energy produced as well as variations in one subarray to another. It is found that the monthly mean energy differences between the subarrays is 74.97 kWh (1.8%), whereas the minimum and maximum energy differences are 12 kWh and 180 kWh, respectively. The local conventional energy cost is 10 cens per kWh. This paper also explores the concept of carbon credits earned (US$ 2684.25) by rooftop grid-connected PV systems, examining the environmental benefits and economic implications associated with the adoption of this technology for natural gas.