Lower circuits of stocks refer to the lower limit beyond which its price can not go on the current trading day. Lower circuits, like upper circuits, are typically calculated as a percentage of the previous closing price. Stocks hit lower circuits when there are many sellers, even at the lower circuit price, but no buyers.
Lower circuits exist for indices as well. Like upper circuits for indices, lower circuits for indices are calculated as a percentage of the previous closing value. They are placed at various levels, which, when reached, lead to halting trading activity for a specified period.
