LONDON, U.K. -- Today’s tutorial under lockdown is about masks.

It was either that, or asking for advice on how to assemble a 1,000-piece jigsaw puzzle. It’s called the Dog Lover’s Jigsaw, featuring 54 of the world’s most popular dog breeds, and was given to me as a Christmas present -- long before anybody knew we’d have plenty of idle time on our hands.

“Enjoy hours of fun with man’s best friend,” reads the label.

So we’re talking about masks instead.

Simple question: Is it necessary, or safer, to wear a mask during this time of global viral plague?

The World Health Organization, which is guiding us through this crisis, says only two types of people need to wear masks: those with COVID-19 symptoms and those caring for people with COVID-19 symptoms.

The rest of us can forget it. There’s no evidence that wearing a mask offers reliable protection. Except that a lot of health specialists now question the WHO’s wisdom.

Why for example, do tens of millions people in Asia wear surgical masks wherever they go? Remember the frenzied lineups at pharmacies in Hong Kong when supplies were being rationed. In some parts of China, you can be arrested and punished for not using a mask.

Two European countries, the Czech Republic and Slovakia, have now made it compulsory to cover your face and mouth when you’re outside. And in the coming days, Austria will begin enforcing an order that all shoppers must wear facial masks in supermarkets.

I’m only asking because for the last week, in this house, we’ve been wearing surgical masks on our one daily escape from lockdown -- the morning walk.

(And yes, Sammy the dog is somewhat adjusting to his new, boring routine of being tethered to a lead. In fact, we’ve put two leads together to give him more space to roam. It’s a long way from freedom, but he can still have a decent run at a squirrel. No, he’s never caught one).

But back to today’s question. A lot of moisture builds up when you’re wearing a mask, and every so often, you need to slip it down and take in a few gulps of fresh air.

Which brings us to this morning’s breakfast conversation:

She: “I wonder how doctors and nurses manage to wear masks all day?”

Out of necessity, we’ve been re-using the same two every day -- recently sanitized in the oven at 70 degrees Celsius for 30 minutes. It’s not perfect, but there’s a shortage, remember.

Many Asians wear masks during hay fever season, or because of air pollution. In Hong Kong, democracy protesters wore masks to evade China’s use of facial recognition technology.

In the age of coronavirus, they’ve become universal, and people are shunned for not wearing one. Because of the Asian experience, American health officials are now considering a change of policy, and so is Canada, apparently. It’s at least under discussion, says Prime Minister Justin Trudeau.

One of China’s leading disease specialists, Dr. George Gao, is blunt about the subject. He thinks it’s a big mistake not to wear masks, convinced they work -- in tandem with curfews, lockdowns and physical distancing.

“You’ve got to wear a mask,” he says, “because when you speak, there are always droplets coming out of your mouth.”

A street cleaner wearing a mask in London, U.K.

(Photo: A street cleaner wearing a mask crosses an almost deserted Westminster Bridge in London, Monday, March 30, 2020. AP Photo/Frank Augstein)

For the moment, the issue seems more about supply than health. Imagine how many billions of surgical masks would be needed to meet the world’s demand.

The evidence is still in dispute, do they work or not? Fear may drive people to wear them anyway, against the latest scientific advice. It certainly can’t hurt, and who’s to tell people they shouldn’t try to protect themselves.

Let me also leave you with this thought. Some Asian-Americans have been physically attacked in the U.S. while they were wearing masks. As the virus spreads, so does hatred it seems.

Goodbye Day 9. We’re heading into double digits.