JACKSON, Miss. (AP) — Mississippi’s capital city has been working to pay a stack of overdue bills the past few months.

The city has paid $9 million since January, reducing the number of outstanding invoices from 470 to 180, Jackson Mayor Chokwe Antar Lumumba said at a news conference Monday, WLBT-TV reported.

The amount due has decreased from more than $9.7 million to $703,000, said Lumumba, a Democrat who has been mayor since July 2017.

“There is a great deal of work still underway. But to be able to reduce that in a sizable way is proof of concept of what we’re working on,” he said. “It’s proof that this work is not only being successful within our departments but we’re headed in the right direction.”

Lumumba spoke about past-due invoices weeks after the issue was discussed by commissioners who decide how to spend money generated by a 1% sales tax in the city of Jackson. The tax is to pay for infrastructure projects, including road repairs.

Commissioner Michael Boerner said he spoke with a contractor who estimated the city owed him $1 million in interest because of not being paid.

In September, WLBT reported reconstruction of Riverside Drive in north Jackson would cost an additional $76,000 after asphalt costs increased as the city delayed paying bills. In October, the One-Percent Commission agreed to pay an additional $850,000 to cover increased engineering costs on the same project after work slowed because of nonpayment.

Also in October, a public records request from the City Council revealed 63 past-due invoices totaling nearly $600,000.

Lumumba said the city’s public works department had 310 outstanding invoices in January. As of July, it had 113.

The mayor said Jackson is working with a team from Bloomberg Harvard City Leadership Initiative on a “procurement makeover” to ensure the city operates more efficiently.