CLASSIFICATION: Rajasthan's lakes fall into two categories based on salinity. FRESHWATER LAKES (मीठे पानी की झीलें) are almost entirely man-made, constructed by rulers for irrigation, drinking water, and aesthetic purposes. SALTWATER/SALINE LAKES (खारे पानी की झीलें) are found in the arid western-central belt and produce salt commercially. There is exactly ONE NATURAL lake in all of Rajasthan — Nakki Lake (Mount Abu, Sirohi) — every other lake was constructed artificially. This single fact appears in almost every REET paper in some form.

PICHOLA LAKE (Udaipur): Built in 1362 AD by Pichhu Banjara (a Banjara grain trader) in memory of his bull, at Pichholi village. Fed by Sisarma and Bujhra rivers from the Aravalli hills. Enlarged by Maharana Udai Singh II when he chose this site for his new capital (after Chittorgarh fell to Akbar). The lake contains two famous islands: JAG NIWAS (now the Lake Palace Hotel, built by Maharana Jagat Singh II, 1743-46) — the James Bond film Octopussy was partly shot here (1983). JAG MANDIR (built by Maharana Karan Singh, completed by Jagat Singh I) — Prince Khurram (future Emperor Shah Jahan) took refuge here from his father Jahangir in 1623. Shah Jahan was reportedly so impressed by Jag Mandir's architecture that it inspired the design of the Taj Mahal. The lake is connected to Fateh Sagar through Swaroop Sagar lake. Pichola's embankment is called 'Badipol'. Maharana Udai Singh's palace (City Palace) stands on the eastern bank.

FATEH SAGAR LAKE (Udaipur): Originally built by Maharana Jai Singh (1678), damaged by floods, restored by Maharana Fateh Singh (hence the name). Connected to Pichola Lake via Swaroop Sagar canal. Three islands: Nehru Park (public garden), India's only Solar Observatory (island 2), and Udaipur Biological Park (island 3). Receives water from Ahar River. UDAI SAGAR (Udaipur): Built by Maharana Udai Singh II, fed by Berach river. Located 13 km east of Udaipur city. SWAROOP SAGAR: The connecting lake between Pichola and Fateh Sagar, built by Maharana Swaroop Singh. These four lakes form Udaipur's interconnected lake system — the reason Udaipur is called 'Venice of the East' and 'City of Lakes'.

RAJSAMAND LAKE (Rajsamand district): Built between 1662-1676 AD by Maharana Raj Singh I by damming the Gomti, Kelwa, and Tali rivers. The construction was a FAMINE RELIEF PROJECT during the severe drought of 1661 — the Maharana employed thousands of drought-affected people in its construction, a remarkably modern concept of disaster relief. The Nauchowki (nine platforms) area on the southern embankment contains the RAJ PRASHASTI — the WORLD'S LARGEST STONE INSCRIPTION. It consists of 25 black marble slabs with 1,017 Sanskrit verses (shloka) composed by poet Ranchod Bhatt Telang, narrating the history of the Mewar dynasty from Bappa Rawal to Raj Singh. Total area: approximately 6.5 sq km. JAISAMAND/DHEBAR LAKE (Udaipur): India's SECOND largest artificial freshwater lake (after Govind Sagar, Himachal Pradesh). Built between 1685-1691 AD by Maharana Jai Singh by blocking the Gomti, Jhaveri, and Bagar rivers. Contains 7 islands — largest: Baba ka Magra (Bhangda), smallest: Pyari. Home to Bhil and Meena tribes on the islands. Two irrigation canals bifurcated in 1950: Shyampura and Bhat canals. Narmadeshwar Mahadev Temple on the embankment was built by Maharana Jai Singh. The lake covers approximately 36 sq km when full.

ANASAGAR LAKE (Ajmer): Built between 1135-1150 AD by Arnoraj Chauhan (known as Anaji — grandfather of Prithviraj III) by damming the Luni river (at its early course near Ajmer). Emperor Jahangir added the Daulat Bagh garden on its banks. Emperor Shah Jahan built five marble pavilions called BARADARI (1637) between the garden and the lake. Subhash Udyan is located on its banks. The lake is approximately 13 km in circumference. FOY SAGAR LAKE (Ajmer): Built in 1892 by British engineer Mr. Foy as a FAMINE RELIEF PROJECT (providing employment during drought). Fed by runoff from the Aravalli hills. Provides drinking water to Ajmer city. PUSHKAR LAKE (Ajmer): One of India's most sacred Hindu lakes with 52 GHATS (bathing steps). The ONLY Brahma Temple in the world is on its banks. According to mythology, the lake was created when Lord Brahma dropped a lotus flower. Annual Kartik Purnima bathing is considered equivalent to performing Ashwamedha Yagna. The Pushkar Fair (Asia's largest camel fair) happens simultaneously. The lake has been suffering from water depletion and encroachment in recent decades.

OTHER IMPORTANT FRESHWATER LAKES: SILISERH LAKE (Alwar): Built by Maharaja Vinay Singh for his queen Shila (1845). Beautiful palace on the embankment, now a heritage hotel (RTDC). BALSAMAND LAKE (Jodhpur): One of the oldest artificial lakes in Rajasthan, built in 1159 AD by Balak Rao Parihar. Now a palace hotel. KAYLANA LAKE (Jodhpur): Built by Pratap Singh (1872) as a famine relief project. Major drinking water source for Jodhpur city — when Kaylana dries up, Jodhpur faces severe water crisis. MANSAGAR LAKE (Jaipur): Famous for the iconic JAL MAHAL (Water Palace) in the middle of the lake. The palace has five floors, of which four remain submerged when the lake is full. Renovated in the 2000s as an architectural conservation project. RAMGARH DAM (Jaipur): Built on Banganga river by Maharaja Sawai Ram Singh II. Formerly Jaipur's main water source (now Bisalpur Dam serves this role). GAJNER LAKE (Bikaner): Built by Maharaja Gaj Singh. Gajner Palace is reflected in the lake. Gajner Wildlife Sanctuary is famous for Kurja (Demoiselle Cranes) migration.

SALTWATER (SALINE) LAKES: SAMBHAR LAKE (Jaipur-Ajmer-Nagaur border): India's LARGEST inland saline lake. Area: approximately 230 sq km (fluctuates seasonally). Produces 8.7% of India's total salt. Designated as a RAMSAR WETLAND SITE. Fed by five rivers/streams: Rupangarh, Khari, Khandela, Mantha, and Samaod. Salt Company: Sambhar Salts Ltd. (government-owned), India's largest salt-producing unit. The origin of salt: NOT from the ancient Tethys Sea (this is a common misconception debunked by Prof. H.S. Sharma). The actual mechanism: micaceous saline rocks beneath the soil release sodium chloride through CAPILLARY ACTION, which rises to the surface and is concentrated by evaporation. Sea water contains magnesium, but Sambhar Lake water does NOT — proving it's not of marine origin. DIDWANA LAKE (Nagaur): Produces sodium sulphate (Glauber's salt). Has a solar evaporation plant. PACHPADRA (Barmer): Famous for high-quality TABLE SALT extracted by the Kharwal/Kharol community through traditional methods. LUNKARANSAR (Bikaner): Smallest major salt lake. KUCHAMAN (Nagaur): Salt lake near Kuchaman city.

NAKKI LAKE (Mount Abu, Sirohi): ONLY natural lake in Rajasthan — this distinction makes it the most frequently tested lake. Altitude: 1,200m (highest lake in Rajasthan). Depth: 35m (deepest lake in Rajasthan). Sacred for the GARASIA TRIBE. FREEZES in winter — one of the very few lakes in Rajasthan that freezes. According to mythology, it was carved by gods using their nails (nakh/nakki = nails). Surrounded by hills with distinctive rock formations: Toad Rock, Nun Rock. Important distinction: all other 'famous' lakes in Rajasthan are man-made. When REET asks 'which is the only natural lake,' 'which lake freezes,' 'which is the highest lake,' or 'which is the deepest lake' — the answer to ALL of these is Nakki Lake.

COMPARATIVE TABLE FOR REET (memorize this framework): Largest by area: Sambhar (230 sq km, saline). Largest artificial freshwater: Jaisamand/Dhebar. Only natural: Nakki (Mount Abu). Highest altitude: Nakki (1,200m). Deepest: Nakki (35m). Sacred lake with 52 ghats: Pushkar. Lake with world's largest stone inscription: Rajsamand (Raj Prashasti). Lakes with islands: Jaisamand (7 islands), Pichola (2 — Jag Mandir, Jag Niwas). Lake built by a Banjara: Pichola (Pichhu Banjara, 1362). Lake with Baradari: Anasagar (Shah Jahan's marble pavilions). Lake with Jal Mahal: Mansagar (Jaipur). Famine-relief lakes: Rajsamand (1661 drought), Foy Sagar (1892), Kaylana (1872), Gajner. Lake freezing in winter: Nakki. Ramsar site: Sambhar. Film location: Pichola (Octopussy). Oldest builder: Anaji Chauhan built Anasagar (1135-1150 AD). REET EXAM TIPS: Lakes appear in 8-10 questions. Match-the-following is dominant (lake↔builder, lake↔district, lake↔feature). Trap: 'Pushkar is the only natural lake' — FALSE (Nakki is). 'Sambhar Lake formed from Tethys Sea' — FALSE (capillary action from subsurface salt rocks). 'Jaisamand is India's largest artificial lake' — FALSE (second largest; Govind Sagar HP is first).