It is tectonic in origin and was almost circular,until frequent landslides made it crescent shaped and has an outfall at the southeastern end.

[1] The Krol group of rocks, comprising slates, marls, sandstones, limestones and dolomites with a few small dykes intrusives, is the dominant geological formation of the lake's surroundings.

[5] The trees and bushes grown in the region (lake's basin) with their botanical and common Indian names (in parentheses) are reported to be: a) Quercus leucotrichophora Oak (Banj); b) Aesculus indica (Pangar or Horse chestnuts); c) Juglans regia (Akhrot or walnut), d) Populus ciliata (Hill Pipal, a sacred tree); e) Fraxinus micrantha (Ash tree or Angu); f) Platanus orientalis (Chinar); g) Rubus lasiocarpus (Hisalu); h) Rosa moschata (Kunj or Musk rose); i) Berberis asiatica (Kilmora);j) Cupressus torulosa (Surai or Himalayan cypress); k) Rhododendron arboreum (Buruns); Cedrus deodara (Deodar); l) Salix acmophylla (Weeping Willow); and m) Pinus (Pine).

A study of the risk assessment code has revealed that 4–13% of manganese, 4–8% of copper, 17–24% of nickel, 3–5% of chromium, 13–26% of lead, 14–23% of cadmium and 2–3% of zinc exist in exchangeable fraction which puts the lake under the low to medium risk category and infers that it could enter into food chain and also cause deleterious effects to aquatic life.

[6] The water quality studies carried out by the National Institute of Hydrology during 1999–2001 on physico-chemical parameters (pH, temperature profile, Secchi's transparency, dissolved oxygen, BOD, COD and nutrients), biological profile (density of population, biomass and species diversity of phyto, zooplankton and macrobenthos) and bacteriological characteristics have led to the conclusion that long-term limnological changes have occurred in the lake.

The lake is thus anoxic and has reduced hypolimnion, winter circulation, large phytoplankton and relatively lower animal population.

[1] The problems facing the lake which were also listed in the plea in a Public Interest Litigation (PIL) before the Supreme Court of India in 1995 seeking court directive for redress measures could be summarised as below:[1] The National Institute of Hydrology (NIH) of Roorkee who prepared a plan for the restoration of the lake, at an estimated cost of Rs 50 crore (about US$10 million), sponsored by the Ministry of Environment and Forests, Government of India, are also now guiding the restoration measures.

The "Nainital Jheel Parikshetra Vishesh Kshetra Vikas Pradhikaran", the Lake Development Authority notified under U.P.

The authorities would examine whether trotting of horses around the lake is also required to be prevented;(iv) Multi-storeyed group housing and commercial complexes have to be banned in the town area of Naini Tal.

Building of small residential houses on flat areas could, however, be permitted;(v) The offence of illegal felling of trees is required to be made cognizable.

In the dead darkness of Kumaon, this magnificence is a distant, partially lit vision, less than real, as the hills of frozen memories make the lake a footnote in water.The Nainital Yacht Club, housed in the Boat House Club, offers yachting facilities at the lake, where a fleet of Half Raters, designed by Linton Hope, sails.

[12] The Kumaon festival which brings out the local cultures and traditions is organized every year during the winter months of October and November, by the Tourism Department.