It's possible you're thinking of:
* The Gangetic Plain: This is a vast, fertile plain in North India formed by the Ganges and its tributaries. It's not technically a Piedmont plain, but it does lie at the foot of the Himalayas, somewhat similar to the concept of a Piedmont.
* The Indo-Gangetic Plain: This is a broader term encompassing the Gangetic Plain and the Indus River Valley. Again, not a Piedmont plain, but it does include plains at the foot of mountain ranges.
* The Coastal Plains: India has extensive coastal plains along both its east and west coasts. These plains are formed by sediment deposition from rivers and the action of the sea.
Piedmont plains are specifically defined as plains located at the foot of a mountain range. While the term is not widely used in India, you could argue that the Gangetic Plain, Indus River Valley, and certain sections of the coastal plains could be considered as such.
If you have more context or specific examples in mind, please clarify and I can provide a more accurate answer.
