Just how dirty is bitcoin mining? Well, the world got a hint of the answer to that question yesterday, when violent protests in Kazakhstan led the government to force a shut-down of the internet to prevent communications among the opposition. That, in turn, closed the nation’s Bitcoin mining operations, largely powered by coal. Independent estimates suggest the result was a 12% drop in global bitcoin production. Fortune’s Shawn Tully explains the how and why.

Meanwhile, an increasing number of countries are joining China in cracking down on crypto mining, with Kosovo—also powered by cheap coal—being one of the latest examples. Some miners are attempting to flee to countries with renewable energy—such as Sweden, Norway and Iceland—but those nations are also moving to restrict new mining to save energy for other uses. Even Kazakhstan is starting to turn away new miners. Tully surveys an increasingly unfriendly global landscape for crypto quarriers here.

Other news below.

Alan Murray
@alansmurray
alan.murray@fortune.com

TOP NEWS

Tech sell-off

Yesterday's big sell-off was largely down to investors taking fright at the prospect of higher interest rates, but it was also a continuation of a massive hedge-fund offloading of tech stocks that has been going on throughout the week. The Nasdaq dropped 3.3% (its worst day since February last year) and some Asian tech indexes slumped this morning. Bloomberg

Kazakhstan latest

Crypto aside, the Kazakh uprising is also having a big effect on uranium prices, as Kazakhstan produces more than 40% of the world's supply. The radioactive metal's price surged around 8% yesterday. Meanwhile, Russia has sent paratroopers to quell the increasingly deadly revolt in its ex-Soviet neighbor. Fortune

Don't drive

In March, car ads in France will start to come with a notice urging viewers to consider carpooling, walking or cycling for shorter trips, or "use public transportation for everyday trips." French food ads carry analogous messages about healthier eating (and don't even mention tobacco ads—those are completely banned in France.) Washington Post

Italian mandate

Italy is introducing a COVID-19 vaccine mandate for the over-50s, and—like Austria, Germany, and now France too—making life harder for unvaccinated people by making proof of vaccination (or of recovery, or of a negative test result) a condition for entering banks, public offices and shops. Fortune

AROUND THE WATER COOLER

Lynn Martin

On Monday, Lynn Martin became just the second woman to become president of the New York Stock Exchange. She told Fortune's Declan Harty: "I obviously understand the gravity of what that means. When I was growing up, this was not a traditional career path that a girl could follow." Fortune

"Herd immunity"

Will Omicron's rapid spread cause "herd immunity" against COVID-19 in the U.S.? Maybe, say the experts, but it may not provide immunity against future variants, and an awful lot of people will die along the way—particularly those who are not fully vaccinated. In hospitals, the scene is complicated right now. Fortune

Unvaccinated Djokovic

Tennis superstar Novak Djokovic is trying to challenge an Australian deportation order that would stop him participating in the Australian Open later this month. The Serbian is not vaccinated against COVID-19 and, after interviewing him, the federal government revoked a medical exemption that the state of Victoria had granted him to enter. Fortune

Long COVID

South African scientists think they may have figured out what causes Long COVID symptoms: microclots in the blood that are resistant to the processes that the body usually uses to break them down, and that don't show up in current pathology tests. Guardian

This edition of CEO Daily was edited by David Meyer.