Air carrier Captain reported being notified by a Flight Attendant of burning odor in the cabin. The Captain conducted a diversion and completed a safe landing.

Narrative

While climbing out of 23;000 ft. we got a call from the Flight Attendants reporting a burning smell in the cabin. They reported that multiple passengers were asking about it and reported some passengers with burning eyes. We immediately [advised ATC] and requested vectors back to ZZZ1. The First Officer took over flying duties and I continued communications with the flight attendants. They reported a haze in the cabin along with the smell; reported as sulfuric and burning plastic. The odor and smoke seemed to be getting worse so we decided to go to ZZZ as we felt like the situation was getting more severe and ZZZ was closer. We ran the Smoke; Fire; Fumes QRC checklist; then followed with the Smoke; Fire; Fumes QRH procedure. We stopped the QRH procedure as the smoke and fumes appeared to dissipate. We landed in ZZZ and pulled off of the runway and had the ARFF crew do a visual exterior inspection. We then proceeded to the gate. The ARFF did an interior inspection looking for any hot spots. None were found. No maintenance was available in ZZZ at the time of our arrival.