What do I do if I do not have a left hand thumb to put the thumb impression while voting?

If your left-hand thumb is missing, then you can give the thumb impression using your right-hand thumb. If the thumbs on both hands are missing, then the impression of one of the fingers of the left hand starting from the forefinger will be taken. If you do not have any fingers on the left-hand, then the impression on the fingers of the right hand will be taken, If no fingers are there on both hands, then you will need to seek assistance of a person whose thumb impression will be taken in the same manner