The phrase "about how essential" is correct and usable in written English.
It can be used when discussing the importance or necessity of a particular subject or topic.
Example: "The article focuses on about how essential it is to maintain a balanced diet for overall health."
Alternatives: "regarding the importance" or "concerning the necessity".
Peter Gelb, the Met's general manager, talks about how essential it is to modernize the theatrical elements of opera.
Mr. Venkatesan has written a book about how essential India is for multinational companies, and why some do "pathetically" here, as he puts it.
When I think about how essential Franny's has been to my wife and me, I am reminded of another restaurant that once loomed large in my life.
We keep talking about how essential it is to radically improve public education while, at the same time, we're closing libraries and firing teachers by the tens of thousands for economic reasons.
When they walked down the street together, and he rested his arm on her shoulder, he thought sometimes about how essential it would be in old age to have someone to lean on.
With all the noise being made about how essential startups and small businesses are to economic growth and stability, you'd think that the powers that be would be a little more eager to help these job-generators protect their assets.
"I'd only heard about it, how essential the Internet was, and I decided that I must learn about it as soon I'm out".
And cities like Washington, DC, which under Chief Cathy Lanier has gone in the opposite direction by having officers go into troubled neighborhoods and hand out business cards as part of a program of community engagement, are seeing their own impressive drops in violent crime, raising doubts about just how essential the old-school Bratton approach is.
There's so much to say about sunscreen--beyond how essential it is.
Leaving the debate about the rights and wrong of unpaid internships aside, Blears reinforces how essential it is that people pick the right work experience opportunities for them.
