CHICAGO (CBS) — Since the City Council approved an ordinance holding banks accountable for vacant properties, the city has collected more than $600,000 in fines from financial institutions.

A Wednesday letter from Mayor Rahm Emanuel to Ald. Pat Dowell (3rd), who sponsored the ordinance, also said the number of registrations of vacant properties citywide risen dramatically.

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The ordinance as originally drafted introduced a legal definition of a “mortgagee” – a bank or other entity that holds a mortgage on a property – as a property owner that is required to handle routine maintenance.

This meant the banks would be responsible for such actions as boarding up entrances, responding to complaints about a building, and keeping the lawn mowed and the snow shoveled.

In the time since the revamped ordinance was approved in October, the number of vacant properties has risen 56 percent to 4,436 through April, compared with 2,883 between October 2010 and April 2011.

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Total fines topped out at $619,000 for the first quarter of 2012, up 123 percent from the $277,200 collected in the first quarter of 2011.

In total, 2,500 violations were issued to more than 150 financial institutions in the first quarter of this year, Mayor Emanuel said in the letter.

In some city neighborhoods, vacant properties have been such a problem that protesters have been willing to get arrested to draw attention to the problem.

Back in October, five women – the eldest 80 years old – were arrested as they dumped trash from a vacant property at 3328 W. Monroe St. in front of the Bank of America Building at 135 S. LaSalle St.

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Mayor Emanuel is hoping for eventual statewide legislation on the issue.