Maryland customers of Washington Gas Light Co. will see their natural gas bills increase, effective Monday. The $8.4 million increase is expected to add $1.27 to the average residential customer’s monthly bill, according to a statement by the Maryland Public Service Commission. The regulatory body rejected the company’s request for a $30 million rate increase, which would have increased Washington Gas’s operating revenue by nearly 6 percent. The body also rejected a request to institute a customer surcharge to pay for infrastracture improvements. — Rachel Babay