Wash rice and take into pressure cooker. Add salt and water.
Pressure cook it for 3-4 whistles or till rice is cooked till soft and slightly mushy.
Once rice is cooled slightly, add yogurt and mix.
You can adjust the consistency by adding water, milk or more yogurt. Also taste and see if more salt is required.
Now to make tadka, heat the oil in a small pan on medium heat.
Once hot add mustard seeds and let them pop. Then add green chilies, ginger and curry leaves. Saute for 30-40 seconds.
Add this tempering to the rice mixture.
Also add grated carrot if using and mix.
Serve this curd rice at room temperature or chilled.
Notes
Add yogurt when rice is cooled slightly or it is warm. If added to hot rice, then yogurt may curdle.
As it cools, it becomes more thick. So based on when you are serving, adjust the consistency by adding milk or water or yogurt. If serving right away then it is fine. If serving chilled or later time, keep the curd rice mixture little loose.