Take sliced onion in a large bowl; add gram flour, rice flour, ginger, curry leaves, red chili powder, baking soda, coriander leaves and salt.
Mix well using spoon and keep aside for 10 minutes.
Add water little by little (about ¼ cup) and mix all the ingredients such that sliced onion is coated well with the batter.
Heat oil in a deep pan over medium flame.
Take small portion of the mixture and gently drop 3-4 small fritters into the oil and deep-fry until they turn golden brown in color – keep stirring occasionally in between so that they cook evenly.
Take them out with a slotted spoon and drain excess oil.
Place the pakoras on paper towel to absorb excess oil.
Repeat the process for remaining batter and deep-fry in batches.