Kankaria Lake, the biggest artificial lake of Ahmedabad located in south-eastern part of the city is studied based on the data of water quality parameters and phytoplankton collected from the literature over one year. The data was categorized into summer, monsoon and winter seasons of the year. The available data is transformed into National Sanitation Foundation Water Quality Index (NSFWQI) and Shannon Diversity Index (SDI) using mathematical equations. The NSFWQI ranges from 70-80 for all the seasons while SDI in the range of 3.4-3.5 indicates the slight pollution level and good water quality of the lake. Through NSFWQI and SDI, it can also be concluded that physicochemical and biological characteristic of Kankaria lake water shows sign of further improvement somewhere between summer and monsoon. The Naviculla Species is found to be dominant among the investigated phytoplankton genera and has great impact on the lake water quality. Further, it is suggested to do an extensive study of Naviculla Species in summer and monsoon for further improvement of lake water quality in future.Read more..