Lake Haleji in Thatta,Sindh,being a wildlife sanctuary had rich biodiversity of fauna and flora in the past.Due to increase in lake pollution,the water has become unfit to plant and animal life.As a result,there is a reduction in biodiversity at the lake and surrounding area.This study focuses on mapping the turbidity (one of the pollution parameters) in the Lake’s water by applying a regression based algorithm using Landsat Thematic Mapper ? data and in-situ water samples collected concurrently with the satellite overpass.A window of nine pixels was selected coinciding with the ground truth locations and a mean of digital numbers from these pixels were utilized to perform atmospheric corrections.In this study,a total of 40 samples were collected from the Lake Haleji to establish an empirical regression algorithm for analyzing the relationship between the concentrations of turbidity and satellite reflectance signals.The efficiency of algorithm was evaluated using determination coefficient R2.The model developed has R2 value of 0.83 which shows a good correlation between satellite driven and in-situ ascertained turbidity values.Moreover,the algorithm was utilized to map the levels of turbidity in the Lake Haleji and Lake Kinjhar (source of drinking water for Karachi) in Thatta,Sindh,and a temporal analysis was carried out on both lakes in the year 1999 and 2011,using the same model.Results of temporal analysis explained that the water of Lake Haleji was not fit for human consumption in the year 2011.There is an increase in turbidity levels (From below 5 NTU in 1999 to around 15 – 30 NTU in 2011) in the Lakes water during the past twelve years which is the clear sign of pollution in the Lake.As far as water of Lake Kinjhar is concerned,there is an increase in turbidity levels but they are within recommended levels (<5 NTU) in the major areas of the Lake.