As more and more people struggle to pay their rent each month in Canada, housing affordability is rising in prominence as a federal election issue.

This week, with just over a month to go until Canadians head to the polls again, a coalition of national housing providers including the Ontario Non-Profit Housing Association released a comprehensive, interactive map to show voters where the rental crisis is hitting hardest.

The 2019 Rental Housing Index is out today, showing a massive and severe lack of housing options for all Canadians across the country. Yet so far, this has barely been discussed in the election campaign. #elxn43 #cdnpoli #affordablehousing https://t.co/naa2FlwVlX

— Jonn Kmech (@JonnKmech) September 17, 2019

Called The Canadian Rental Housing Index, the tool allows anyone to sort through several data sets by province, municipality, regional district or federal riding.

The subsections include breakdowns of the number of rental households, the average cost of rent, income gaps, overcrowding and overspending in any given region.

Most interestingly for Toronto, where affordable housing is top of mind for urban planners, is an index that measures the percentage of renters living "affordably" by riding based on 2016 long-form census data.

Here are the top 20 ridings where the rental housing affordability crisis is at its peak #elxn43 #RentalHousingIndex pic.twitter.com/lKVx1ULOfU

— Courtney Lockhart (@COURT_LOCK) September 17, 2019

"Affordability measures the proportion of income renter households spent on rent and utilities," reads the index's subheading. "Housing is typically considered affordable if a household spends less than 30% of its before-tax income on rent plus utilities."

The top five least affordable federal ridings out of 338 Canada-wide can be found in the GTA.

Over half of all renters living in Willowdale, Thornhill, Richmond Hill, Markham and Rosedale are spending more than 30 per cent of their incomes on rent each month, according to the index.

More than 30 per cent of that same group spend more than 50 per cent on rent, putting them well into "overspending" territory.

Are you curious what the #affordablehousing situation is in your community? The #RentalHousingIndex allows you to find infographics on housing affordability in communities across Canada: https://t.co/eWVXGTEIOq pic.twitter.com/kZHXtHJyaj

— CHF Canada (@CHFCanada) September 17, 2019

"Willowdale, in Toronto, takes the title as the federal riding with the highest proportion of renter households dealing with a crisis level of spending on rent," reads a release from the Canadian Rental Housing Index published Tuesday.

"In that riding, nearly two-thirds (59 per cent) of all renter households spend 30 per cent or more of their income on housing, while 39 per cent allocate half or more," it continues. "Neighbouring GTA ridings of Thornhill and Richmond Hill are not much better, placing second and third most unaffordable in the country."

So, not only are these parts of Toronto some of the least affordable for renters in Ontario, they're some of the least-affordable in Canada.

You can check out the entire index here, and learn more about the plights of those most-affected by the rental housing crisis: Seniors, single mothers and indigenous renters.