NEW YORK (Reuters) - New York Mayor Bill de Blasio, who is considering a run for the White House in 2020, on Monday threatened to fine the Trump Organization $2.1 million a year starting in 2030 unless the president’s business reduces emissions from its buildings.

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“It doesn’t matter who you are, even the president of the United States, you have to obey the laws of New York City,” de Blasio said at a rally in the lobby of Trump Tower, the site of President Donald Trump’s private home and business headquarters.

As the Democratic mayor spoke, counter-demonstrators raised signs behind de Blasio calling him a “failed mayor” and supporting the president’s re-election campaign with “Trump 2020.”

A New York City law due to take effect on May 17 sets emissions standards for large buildings like Trump Tower, a 58-story skyscraper on Manhattan’s Fifth Avenue.

Buildings are responsible for nearly 70 percent of greenhouse gas emissions in the city, the mayor’s office said in a statement. But the mayor so far has named only the Trump Organization as a potential offender.

De Blasio is considering joining more than 20 other Democrats in a run for the 2020 presidential nomination. He said the decision to hold a rally in the lobby of Trump Tower was independent of any presidential ambitions and he promised to name other potential violators publicly in the future.

Eight of Trump’s buildings in the city fail to meet the 2030 emissions standards, releasing about 27,000 metric tons of greenhouse gases each year, or the amount produced by 5,800 cars, de Blasio’s office said.

The Trump Organization, which includes about 500 businesses in which the president is sole or majority owner, did not immediately respond to a request for comment or to address the level of emissions purported by the city. After his 2016 election, Trump stepped down from his executive positions at the company but retained his financial stakes.

Trump Tower faces a fine of $469,848 per year if no improvements are made, the mayor’s office statement said. Another Trump property, the Trump International Hotel & Tower, faces fines of $850,871 per year.

The law on buildings emissions is part of the city’s Green New Deal initiative, which aims to reduce emissions 30 percent by 2030 and adhere to the standards of the Paris Agreement, an international pact on climate change from which Trump withdrew the United States.

Trump rejects climate science that links rising temperatures to human consumption of fossil fuels. Instead, he has promoted deregulation of the energy sector, which the president says will foster economic growth.