Achaari Alu or Tangy Potatoes

Name: Achaari Alu or Tangy Potatoes
Ingredients: 5 potatoes, peeled and diced; 1 onion, finely minced; 2 teaspoons ginger-garlic paste (if you dont have this and want to make it- great for indian as well as chinese cooking. Chop equal q); 1⁄2 teaspoon turmeric powder; 1⁄2 teaspoon chili powder; 2 teaspoons sugar; 2⁄3 cup water; 3 tablespoons lemon juice; 4 dried red chilies; 1⁄2 teaspoon mustard seeds; 1⁄2 teaspoon cumin seed; 1⁄2 teaspoon nigella seeds (kalonji- optional available at indian stores); salt; 1⁄4 teaspoon asafoetida powder (hing) (optional)