Find the odd number / letters / word from the given alternative.

Dispur
Panaji
Shimla
Leh E. Aizawl

The odd one out is D. Leh. The other four options are all capital cities of Indian states, while Leh is a union territory.

Dispur is the capital of Assam.
Panaji is the capital of Goa.
Shimla is the capital of Himachal Pradesh.
Aizawl is the capital of Mizoram.