Hydrogen to fuel Tokyo 2020 Olympic flame

A pure hydrogen flame is almost invisible, particularly in daylight. Perhaps some impurities will be added to brighten it up.

How is the hydrogen fuel produced? Most is made through burning coal and gas, making it a dirty fuel. It can be made by renewable power, but Japan's adoption of renewables has been slow compared to other developed countries, probably because those countries are more interested in doing something rather than staging dubious PR events.

How to say gimmick in Japanese?

“The Olympic Flame, Presented by Toyota’s wildly over optimistic hydrogen fuel cell ambitions, and now we have to do something to make it look like a viable fuel source.”

hydrogen isn't clean it's made from fossil gas or other processes. Unless it's hydrolysis it's just any other fuel. Methane from kitchen waste bio-digesters would be easier and not require some large manufacturing process

"The plan is in synch with Tokyo 2020 being branded as "the Reconstruction Olympics""

You mean because it has done NOTHING towards reconstruction since milking the disasters to win the bid? Oh, well, great! Allowing one small company's product makes up for ALL the money wasted that could have given lives back to people STILL in shelters.