Ingredients:

1/2 kg lemon, washed and dried
100 gms ginger, washed and peeled
21/2 tbsp salt
21/2 tbsp black salt
11/2 tbsp red chilli powder
1/4 tsp asafoetida
1 cup sugar
3 tbsp ajwain
1/4 tbsp crushed mustard seeds
1 tbsp garam masala

Method :

Give 4 cuts to lemons, keeping the whole lemon intact
Grate the ginger
In a steel vessel, put all the ingredients
Mix it well and fill the lemons.
Tie the vessel with muslin cloth
Keep it sun for 30 days
Store in air-tight container