LONDON, U.K. -- Today鈥檚 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鈥檚 called the Dog Lover鈥檚 Jigsaw, featuring 54 of the world鈥檚 most popular dog breeds, and was given to me as a Christmas present -- long before anybody knew we鈥檇 have plenty of idle time on our hands.

鈥淓njoy hours of fun with man鈥檚 best friend,鈥 reads the label.

So we鈥檙e 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鈥檚 no evidence that wearing a mask offers reliable protection. Except that a lot of health specialists now question the WHO鈥檚 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鈥檙e outside. And in the coming days, Austria will begin enforcing an order that all shoppers must wear facial masks in supermarkets.

I鈥檓 only asking because for the last week, in this house, we鈥檝e 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鈥檝e put two leads together to give him more space to roam. It鈥檚 a long way from freedom, but he can still have a decent run at a squirrel. No, he鈥檚 never caught one).

But back to today鈥檚 question. A lot of moisture builds up when you鈥檙e 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鈥檚 breakfast conversation:

She: 鈥淚 wonder how doctors and nurses manage to wear masks all day?鈥

Out of necessity, we鈥檝e been re-using the same two every day -- recently sanitized in the oven at 70 degrees Celsius for 30 minutes. It鈥檚 not perfect, but there鈥檚 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鈥檚 use of facial recognition technology.

In the age of coronavirus, they鈥檝e 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鈥檚 at least under discussion, says Prime Minister Justin Trudeau.

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

鈥淵ou鈥檝e got to wear a mask,鈥 he says, 鈥渂ecause when you speak, there are always droplets coming out of your mouth.鈥

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鈥檚 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鈥檛 hurt, and who鈥檚 to tell people they shouldn鈥檛 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鈥檙e heading into double digits.