Boston City Councilor Michelle Wu announced she is running for mayor against incumbent Marty Walsh by saying Boston should be a city for everyone, that systemic problems our society is already grappling with — like the opioid epidemic — have only been made worse by COVID-19, and that leaders need to be bold to meet the moment.

Wu told Boston Public Radio on Wednesday that the Walsh administration is "failing so many people" in its response to the opioid epidemic, specifically in the troubled area of Melnea Cass Boulevard and Massachusetts Avenue.

"The so-called plans put forward by the administration so far have been largely public works and law enforcement-oriented plans — how do we pick up needles as quickly as possible or clean up human waste on the sidewalks as quickly as possible," she said. "But we still don't have a citywide plan to address homelessness and our substance use epidemic right now that is shifting and growing, and at the heart of this is how we're going to solve the public health crisis."

Wu had previously called Walsh's response at Melnea Cass/Mass. Ave. "cruel," when police officers swept the area last summer, arresting dozens. The area is home to a number of recovery clinics, hospitals and shelters. Wu said the city needs to spread out its resources.

Walsh, on Boston Public Radio last Friday, acknowledged that the detereorating situation at Melnea Cass and Mass. Ave. is "one of the biggest challenges" the city has to contend with, when a South End resident called in to describe the now common sight of human waste on sidewalks, stoops and parks.

He cited the city's office of recovery services, which opened under his watch and is available to everyone in the city — not just those around Melnea Cass and Mass. Ave., known disparagingly as "methadone mile" — but noted that resources have been spread thin due to COVID-19.

"Part of the situation out there does deal with coronavirus," Walsh said, noting that it has been harder to get people into treatment with courts in flux. "We also had a lot of services around the commonwealth in the city cut in half because of coronavirus, so a lack of services" is contributing to the worsening situation.

Wu had ramped up her opposition to Walsh's policies as city councilor for months, and voted against his budget, which ultimately passed after heated debate over whether the budget went far enough to address race and policing policies. On the issue of addiction, Wu said the city needs to seek a more comprehensive response.

"At the heart of this is how we're going to solve the public health crisis," she said. "We don't have housing that's affordable, trauma goes untreated, and we have a growing epidemic of folks turning to substance use as a way to self medicate, and then not having access to the treatment on demand or shelter or safety that they need to access that treatment. Once we take care of that sitaution, all of the other symptoms of it, the health impacting the neighborhood, the experience of residents, are connected to that. It's actually one and the same."

Wu also discussed other aspects of her platform, including her advocacy for a fare-free MBTA and the adoption of a local Green New Deal.