Combine the red chillies, garlic and salt in a mixer and blend till smooth using approx. 2 tbsp of water.
Transfer the mixture into a bowl, add the lemon juice
Heat the oil in a small non-stick pan, add the mustard seeds and asafoetida and sauté on a medium flame for a few seconds.Add this in the mixture and mix it well.
Store in an air-tight container and refrigerate.