The Democratic primary debates for September and October have significantly more strict qualifying thresholds, and the 2020 presidential field has thinned out considerably.

Candidates had to reach 2% in at least four separate polls approved by the Democratic National Committee and receive at least 130,000 individual donations, which must also include 400 donors in at least 20 states or US territories.

In total, 12 candidates met both thresholds to qualify for the October debate, which will be hosted by CNN and The New York Times in Westerville, Ohio tonight, October 15.

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A grand total of 12 Democratic presidential candidates will be on stage for the DNC debate taking place tonight, October 15, in Ohio.

The number of donors candidates had to receive was doubled to a minimum of 130,000, with at least 400 donors coming from 20 different states or US territories. The candidates also had to obtain at least 2% in four separate national or early-state polls approved by the Democratic National Committee.

And unlike the first two sets of debates in June and July, candidates had to meet both the polling and donor minimums, instead of being able to qualify but meeting just one of them.

Read more: Here's who will be onstage for tonight's Democratic debate hosted by CNN and The New York Times, what time it'll start, and how to watch

The stricter debate requirements have considerably thinned out the field.

Since late August, Gov. Jay Inslee, former Gov. John Hickenlooper, Rep. Seth Moulton, Sen. Kirsten Gillibrand, and Mayor Bill de Blasio all dropped out of the race after they failed to qualify for the fall debates.

In total, these 12 candidates met both thresholds to qualify for the October 15 debate, which will be co-hosted by CNN and The New York Times at Otterbein University in Westerville, Ohio.