-Ghanshyam Kalki Pande and Pradeep Mehta, CHINAR (Central Himalayan Institute for
Nature & Applied Research)
Nainital Lake, a natural freshwater body, situated at the centre of Nainital town in the Uttarakhand state of India. Nainital lake finds mention in the Manas Khand (chapter) of the Skanda Purana as the Tririshi Sarovar (lake of three sages – Arti, Pulastya and Pulaha. The majority of the local people believe that the eyes of Sati dropped in the lake while her body was being carries by Lord Shiva to Kailah Parvat. Thus, it got its name Nainital or Naini lake.
High and steep Nainia peak at the North West, Tiffin top at the south and Snow view on the north side create a basin around the lake. These slopes are covered with dense forests. These forests proved a home to many species of animals and
resident and migratory birds. More than 250 bird species could be easily seen at this area in a year. 
Since past few years, the ecosystem of the lake and its surroundings is rapidly changing. Many species of birds and insects are disappearing very fast. The water level of lake is now decreasing to its lowest levels every year. All this is happening as a result of man- made activities such as an outbreak of human population in town and increasing number of tourists / visitors at an uncontrolled manner. During last few years the number of small and big vehicles has increased at alarming level and as a result of all these activities, the average temperature of the town is increasing every year. The average water level of lake is rapidly decreasing since last 2-3 years (2015-17). Last year it was at alarming low level of approximately 12 feet.
Many species of birds which used to be found around the lake area are either moved to nearby water bodies or their population is decreasing very fast. Earlier there were at least two resident species of kingfisher around the lake area i.e., White breasted kingfisher (Halcyon smyrnensis) and common blue kingfisher (Alcedo atthis). These species are now completely moved to the nearby water bodies such as Sattal and Naukuchiyatal lakes. Some other bird species like little heron(Butorides striatus) was also very common at Naini Lake, which is also quite rare to spot now. Earlier, a variety of dragon flies and other water insects was very common at the banks of the lake, they used to feed on the aquatic plant cover on the banks of the lake. But now as there is no aquatic plant cover, these species are also disappeared.
This aquatic vegetation cover was also a perfect nursery for fishes, frogs and insects like dragon flies and water bugs to lay their eggs. It was also a perfect hideout for small fishes and tadpoles. Many birds like kingfishers and herons used to feed on these small fishes and tadpoles. May be the lack of food is a reason of their permanent migration from Naini lake area. Although a healthy population of big fishes i.e., Carps and Mahaseer is still present in the lake and because of this, a new species of bird, the Great cormorant (Phalacrocorax carbo) has now become a resident species of the Naini lake area.
A number of other bird species like Siberian Rubithroat (Luscinia calliope), Bluethroat (Luscinia svecica) and Himalayan Bluetail (Tarsiger cyanurus), which were winter visitors are also very hard to spot now. The population of Wagtails, Redstarts and Tits is also decreasing every year. A frequent winter visitor Steppe eagle (Aquila nipalensis) which was very common on the rocky slopes near Hanumangarhi temple during winters, has also moved from here (The reason behind it could be the shifting of Garbage dump yard of Nainital from Haniumangarhi area). A very common species of insects called ladybird (Coccinellids) which used to be found in large numbers in Nainital area during summers, have become very limited. These insects were a main source of protein for bird nestlings during spring season. Another species of bird which is rapidly increasing its population in Nainital area is Rock Pigeon (Columba livia). This species is now becoming a threat to House Sparrows (Passer domestica) as they take over the nesting areas and feeding areas of House Sparrows.
The infrastructure around the town is changing very fast. Construction in the past three decades happened at a massive pace and is still continuing. Almost all walking paths on the hills are now converted into cemented roads thus minimizing the percolation rate and increasing the runoff. Decrease in percolation has resulted in less recharge of ground water or acquirers resulting in extinction of many springs. Increasing no of vehicle, Electronic appliances in the houses are now affecting the micro climate of the town and its surrounding areas. The average temperature of the town is increasing day by day which is adversely affecting the average snowfall which is now decreasing every year. Snow is one of the main resource for the ground water and recharge of springs even for the germination of many tree species
To overcome the situation, a scientific and sustainable action plan for the development and sustainability of the town as well as conservation of its micro climate and ecosystem is now an urgent requirement to save this beautiful water body and the town for the next generations.