Preheat oven to 200ºC (400ºF).
Peel pumpkin skin, remove seeds, and cut pumpkin into 2cm thick, evenly sized wedges.
Place pumpkin wedges on a large baking tray.
Add ground cumin, garam masala, red chili powder, olive oil, salt, and pepper.
Toss until evenly coated.
Arrange wedges in a single layer on the tray, leaving space between them.
Roast for about 30-40 minutes, until tender, browned and caramelized on the edges.
Finish with a light drizzle of fresh lemon juice.