250. An Unclean Place

Kriyas Shema 3:13

One may not recite the Shema while facing excrement floating on the water. The mouth of a pig has the same rule, so one may not recite Shema facing it until he has moved four cubits (six feet) away from it.

Kriyas Shema 3:14

If one is walking and saying Shema, then he comes to an unclean place, he should not place his hand over his mouth and keep reciting. Rather, he should stop saying Shema until he has passed this place. Similarly, if one is saying Shema and breaks wind, he should stop reciting until the odor passes, then he may resume. The same rule applies to a person who is studying Torah. If another person breaks wind, one must pause reciting Shema but he need not stop studying Torah.