Indians have traditionally eaten with their right hand and sometimes wooden(and later metal) spoons, depending on the dish. Indians have traditionally not eaten with chopsticks.

Other redditors have already explained the history of Indian utensils, so I'll answer the OP's question about the "chopstick Mason-Dixon line." Chopsticks were traditionally exclusive to East Asia. They were invented by the Chinese and are common utensils in countries within the Chinese cultural sphere, like Japan, Korea, and Vietnam. East Asian diaspora populations brought chopsticks to Southeast Asia, North America, and Europe. The history of chopsticks dates back to the Spring and Autumn period (c. 600 BC):

Chopsticks are, of course, the best known and most characteristically Chinese eating implement. According to the Records of the Grand Historian, 90 BC, by by Sima Qian, King Zhou, the last ruler of the Shang dynasty, was the first person to have made a pair of chopsticks out of ivory, which implies that chopsticks must have been known before King Zhou's time, that is, before 1100 BC... There is, however, no textual or archaeological evidence in support of Sima Qian's account. The earliest archaeological record of chopsticks was found in a tomb southeast of Dali, Yunnan. Among the bronze artifacts discovered there were two pairs of chopsticks and several spoons. The tomb was dated at sometime in the middle Spring and Autumn period (c. 600 BC)

Needham, Joseph. (2000). Science and Civilization in China: Volume 6, Biology and Biological Technology Part 5, Fermentations and Food Science. Cambridge University Press. p. 104