Now for the sauce,heat oil in a pan and add the chopped garlic,ginger and green chilies.saute till the raw smell goes.Now add chopped onion and spring onion and saute for a minute,add chopped bell pepper.Cook for few minutes.Add chilli powder and mix well.Add soya sauce,tomato ketchup,salt to taste and required amount of water,bring to a boil.Now mix cornflour with 1/4 cup water and add it to the sauce.Mix well.When the sauce thickens add the manchurian balls and switch off the gas.