Heat the oil in a pan. To the heated oil put mustards and allow them to pop. Then add turmeric, hing, chana dal. As soon as the chana dal turns brown put curry leaves, green chillies and as then add grated mango and saute it for few seconds(say, 20-30). Remove it from the heat.
Add the above mango vaggarini to the cooked rice.
Note:If mango is not sour you can add lime juice.