Interesting, I don't have a key at hand, but I looked up a machinist table and  the width is easy to measure on your shaft but the size that is a bit challenging is the diameter, and I found that they come in certain standard diameters. I don't know if it is applicable on the Indian, if they used some special, but here you have it in inch: 0.25-0.312-0.375-0.5-0.625-0.75-0.875-1.0-1.125-1.25-1.375-1.5 and so on.