Well, onions contain a oil, which has lots of sulphur in it. When you cut the onion, this oil is released. It evaporates very fast. When the oil gases reach your eyes, it causes irritation and sends signals to your tear gland to produce tears. So that the tears can wash away the irritant from your eyes.
wenzao wanavaaga kofia za upishi na miwani..hii low cost solution ya kuvaa helmets za bajaj ina-advantage kwamba pia unaipa mazoezi misuli ya shingo..heheee.