The phrase "and is closely based" is correct and usable in written English.
It can be used to indicate that something is derived from or heavily influenced by another source or idea.
Example: "The new film is a sequel to the original story and is closely based on the characters and themes established in the first movie."
Alternatives: "and is heavily influenced by" or "and is strongly derived from".
The Rom, which takes its name from the nearby river, was built using seamless pressurised concrete and is closely based on Californian skateparks.
This survey asks students to rate 31 statements on a Likert scale of "strongly disagree" to "strongly agree" and is closely based on the physics CLASS (Adams et al., 2006), which has also been adapted for chemistry (Barbera et al., 2008).
All four industry bodies, including the Newspaper Society, which represents national and local titles, are backing the plan which is closely based on the draft charter the industry agreed with the government on 12 February.
Posy Simmonds's graphic novel, on which it is closely based, is a loose and whimsical adaptation of "Far From the Madding Crowd," Hardy's 1874 novel about the romantic travails of Bathsheba Everdene.
The video for "Only This Moment" is closely based on the events of the Paris 1968 riots, and elements of propaganda are found throughout the video clip.
The King is closely based on the life of Naser al-Din Shah Qajar, who ruled Persia from 1848 to 1896.
The European human rights convention, on which the 1998 act is closely based, is "an entirely sensible statement of the principles which should underpin any democratic nation".
Maybe he was right, if the people were Western, because Esperanto is closely based on Indo-European languages, or the ones that Zamenhof knew best.
The setting of Breakfast with the Nikolides is closely based on Narayanganj, with the bazaar lying "like a patch of plague" against its walls.
Sometimes this results in a poem that is closely based on a particular rhyme, in other instances it can be more to do with a general tone.
