Research Journal of Chemical Sciences ______________________________________________ISSN 2231-606X Vol. 13(2), 23-28, June (2023) Res. J. Chem. Sci. International Science Community Association 23 Current scenario of limnological characteristics of Pushkar lake, Rajasthan, India Pooja Tak*, Rounak Choudhary, Vivek Sharma and Subroto Dutta Department of Environmental Science, Maharshi Dayanand Saraswati University, Ajmer, India poojatak313@gmail.com Available online at: www.isca.in, www.isca.me Received 19 th December 2022, revised 3 rd January 2023, accepted 10 th May 2023 Abstract Lakes are a unique entity, where physical, historical, cultural, social, administrative, or functional elements come together to create a tourist reality that is both spatial and practical. For locals, lakes and reservoirs in dry and semi-arid environments are a major source of water. In recent decades, there has been concern about how people interact with water bodies. All tourist activities in the town of Pushkar depend on Pushkar Lake. The lake experiences an increase in biochemical oxygen demand (BOD), alkalinity, water hardness, chlorine, fluoride, and nitrate levels as a result of the millions of people who bathe there and participate in other religious activities almost all year long. Samples were gathered in PET bottles using conventional methods. To estimate the quality of drinking water, Horton's Water Quality Index (WQI) was used. All of the analysis techniques adhered to the prescribed protocols as per the techniques described in APHA. This research reveals that the water in Pushkar Lake was slightly alkaline. The total alkalinity of water depends on the kind and quality of its constituents, including bicarbonate, carbonate, and hydroxide. The range of TDS values ranged from 332ppm to 462.37ppm. Pushkar Lake had a minimum total hardness of 185.75mg/lt during the study period. The Pushkar Lake's WQI value, which ranged from 94.67 to 124.01, indicated that the water was unfit for drinking. Pushkar Lake's primary source of hardness is the addition of calcium and magnesium through surface run-off during the rainy season. Because of its spiritual significance, Pushkar Lake is revered and visited by pilgrims. Due to the lake's small size and delicate ecology, an increase in tourist activities has had a detrimental effect on its water quality. To address the problem, regular monitoring of water quality is also necessary. Keywords: Pushkar Lake, Limnology, Physico-Chemical Analysis, Water Quality Index. Introduction Water is a crucial element for human and industrial development, as well as the most vulnerable component of the environment 1 . Each destination is a distinct entity in which physical, historical, cultural, social, administrative, or functional aspects combine to create a spatial and functional tourist reality. As a tourist destination, a lake is usually a functionally compact regional whole with identifiable geographical limits. Lakes and reservoirs in dry and semi-arid environments provide a significant source of water for local residents. The interaction of man with water bodies has been a source of concern in recent decades, owing mostly to fast population increase, which has resulted in water body degradation from home, industrial, and agricultural run-off carrying fertilizers and pesticides 2 . Lakes and reservoirs throughout the country have varied degrees of environmental degradation 3 . Significant sources of water pollution are public bathing, the disposal of dead corpses, rural and urban trash, and solid waste disposal 4 . Hydrological factors such as precipitation, water loss due to high heat indices, and man-made perturbations can change the chemical and physical properties of water, and these changes in the physico-chemical environment have a direct impact on the biotic component of the water body 5 . The water quality index (WQI) is one of the most effective instruments for communicating water quality information to concerned citizens and policymakers. WQI measures the overall water quality of a specific location and time. It has evolved into a key measure for assessing and managing water quality for human use 6-8 . Water is considered to be a passive carrier for a variety of organisms, including bacteria, viruses, and protozoa, which can cause a variety of ailments in people. The presence of indicator organisms in water is thought to be a critical component in determining pathogen-caused health problems is currently regarded as ideal fecal indicator bacteria for the global monitoring of fecal contamination in drinking water quality standards and guidelines. The amount of indicator organisms in drinking water should be undetectable in a 100ml sample, according to WHO 9 . Because the bulk of such environmental issues are caused by humans, increased human activity in the catchment region of many aquatic systems has affected the natural processes of these systems, threatening the existence and expansion of biotic communities 10 . One such pilgrim lake is Pushkar Lake, which is important to all tourist activities in the town of Pushkar. The demands of society for economic gain have contributed to the decline of lake water quality and scenic value 11 . Pushkar's survival is largely dependent on the lake.