Pluck the mint leaves and discard the stems. Keep the leaves in a bowl of water for 5-10 minutes, let the dirt settle at the bottom. Similarly, add cilantro with stems in the water. Then gently remove leaves, lightly squeeze to remove excess water, and add it to the blender jar.
Add rest of the ingredients (salt, sugar, green chilies, ginger, chaat masala, lemon juice, little water) into the blender jar.
Blend till everything is smooth.
Video
Notes
Adjust the number of green chilies as per your liking spice level.
The stems of the mint make the chutney bitter. So always discard the stems and use only mint leaves to avoid bitterness.
Lemon juice is a must, do not skip it. It acts as a preservative and keeps the chutney fresh. Also, it helps to retain the green color of the chutney. Plus adds a nice flavor.
Do not add too much water otherwise, chutney becomes runny and dilutes the flavors. So always start with little water and add more if needed. Water quantity may vary depending on how much water is held on by leaves after washing/rinsing.