Peel and halve the onion and cut into strips. Peel garlic and finely chop. Rinse, the pumpkin and cut into small pieces.
Halve the zucchini lengthwise and slice crosswise.
Heat the oil in a large skillet. Add the onion, ginger, garlic, zucchini and pumpkin and cook over high heat , stirring frequently until crisp-tender, 4 - 5 minutes. Stir in the coconut milk, curry paste and lemon juice, season with salt and pepper, and simmer over medium heat until piping hot, about 3 minutes. Add the shrimp and simmer just until hot, then serve in bowls garnished with basil.