• CNBC's Jim Cramer on Thursday slammed world leaders for failing to contain the spread of the delta Covid-19 variant.
• "I put this sell-off squarely in the laps of politicians around the world, because we right now have a failure of global leadership," the "Mad Money" host said.
• "If we get the COVID variants under control by forcing people to get vaccinated, I think bond yields and the stock market will start rising again," he said.

CNBC's Jim Cramer came out swinging on Thursday, blaming the market sell-off on world governments and slamming leaders for failing to get a grip on the spread of a Covid-19 variant.

Major U.S. stock averages all plunged almost 1% during the session, dropping the S&P 500 and Nasdaq Composite indexes from record highs. Health concerns also led to a drop in bond yields to levels not seen since February.

The declines can be attributed to the delta strain that's spreading quickly across the globe, Cramer said.

"I put this sell-off squarely in the laps of politicians around the world, because we right now have a failure of global leadership," the "Mad Money" host said.

"Here in America, we're doing a much better job of getting people vaccinated than most countries, but we screwed up when we made the vaccination process voluntary."

Cramer lambasted that the U.S. Food and Drug Administration has yet to give full approval to coronavirus vaccines from the likes of Moderna and Pfizer-BioNTech. Three vaccines, including a one-shot solution from Johnson & Johnson, have been authorized by the agency for emergency use to combat the health crisis and administered to millions across the country.

Pfizer applied for FDA approval of its vaccine in May, followed by a submission by Moderna for its own product in June.

"Maybe you think this is a technicality, but so many Americans don't trust the vaccines and the lack of FDA approval sure doesn't help," Cramer said. "I challenge the FDA to explain themselves and their foolhardy behavior."

The delta variant, which was first discovered in India and is spreading quickly across the globe, is now the dominant strain affecting people in the U.S. Despite America's elevated vaccination rates in comparison to most other countries, the delta outbreak elsewhere in the world could portend breakouts in communities here vaccination rates are lagging.

Health experts say that indoor mask mandates and public health measures may need to be reinstated to slow the delta variant's spread in the country.

"If we get the COVID variants under control by forcing people to get vaccinated, I think bond yields and the stock market will start rising again," Cramer said. "I don't see much hope for speeding up vaccinations without either paying people money or coercing them, neither of which is going to happen in this country.

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