With hoots, hollers, and chants of 'chug, chug, chug,' thousands of green-clad revellers descended on a Waterloo, Ont. street Saturday to celebrate Saint Patrick’s Day.

Amid a large police presence, the street in the university and tech town was thronged by noon with students swigging green-hued beer. Police worked to contain the crowd at the unsanctioned street party, shutting down Ezra Avenue and issuing ticket after ticket, and even making several arrests.

At the party’s peak, paramedics were answering calls roughly every five minutes. Nearly all were alcohol-related.

“That is 50 per cent extra of our normal call volume throughout the region just in this three block radius,” Robert Crossan of the Region of Waterloo Paramedic Services told CTV Kitchener. “So it’s a big deal for us.”

Officials said 25 revellers were hospitalized by the time the street party was finally shut down by police around 6 p.m. That number is expected to rise as parties continue well into the night.

In 2017, Waterloo paramedics transported 44 people to hospital on St. Patrick’s Day.

While no estimate of the crowd size was available Saturday, it appeared to be well above the 15,000 who showed up for the annual -- and unofficial -- street party last year.

“Ezra right now is more insane than Dublin, Ireland on Saint Patrick’s Day,” one partier boasted to CTV Kitchener. “It’s nuts!”

Police pushing through the crowds on Ezra. #stpatricksday pic.twitter.com/0APbd5icyj — Tina Yazdani (@TinaYazdani) March 17, 2018

Thousands of students have already shut down Ezra... more crowding in every minute. Police say they’re cracking down this year #stpatricksday pic.twitter.com/B5lg27UFrD — Tina Yazdani (@TinaYazdani) March 17, 2018

Students get really excited when they see the CTV camera #stpatricksday pic.twitter.com/axVzc1UYn1 — Tina Yazdani (@TinaYazdani) March 17, 2018

Sea of green. Crowd swelling on Ezra #stapatricksday pic.twitter.com/xAF9c6V0QI — Tina Yazdani (@TinaYazdani) March 17, 2018

Dozens of officers just pushed through what was left of the crowd, clearing Ezra Ave. Students gone but lots of trash left behind. #StPatrickDay pic.twitter.com/rRhIRMh7Oa — Tina Yazdani (@TinaYazdani) March 17, 2018

With a report from CTV Kitchener’s Tina Yazdani