Which one of the following is an artificial lake?

Answer: (a) Kodaikanal (Tamil Nadu)

Kodaikanal lake was created in 1863 by damming streams — it is man-made.

The idea

An artificial lake forms because people create or deepen a basin or block drainage. A natural-looking shore or a hill-station setting does not reveal its origin. The deciding test is how the water body formed, rather than its altitude or present use.

People block small stream outlets → Water backs up → A basin fills → An artificial lake takes shape → Managed outlets control its level

Why the others are wrong

(b) Kolleru is a natural freshwater lake between the Krishna and Godavari deltas.

(c) Nainital is a natural lake in a tectonic depression.

(d) Renuka is a natural lake in Himachal Pradesh.

The trap

Hill-station lakes are not all artificial — Nainital is natural.

Also know

Hussain Sagar in Hyderabad and Jaisamand in Rajasthan are other artificial lakes. Gobind Sagar is a river reservoir, rather than a small town lake. Wular and Renuka are natural lakes. Natural lakes can also have managed outlets without becoming artificial in origin.