I adhere to the opinion expressed by Oxford Dictionary:

" In standard English, 'less' should only be used with uncountable things ( less money, less time). With countable things, it is incorrect to use 'less' ( 'less people' and 'less words'); strictly speaking, correct use is 'fewer people' and 'fewer words'.

Descriptive grammar fails to take into account whether the expression comes before the noun, or after.

more than 10 items
fewer than 10 items

10 items, more or less
10 items or less

My two sisters and John are definitely coming to the party.
compare
There is/There's John and my two sisters who are definitely coming, with Paul as a 'maybe'.

Judging by the examples of descriptive grammar I see every day, then "There is people in this world who…" would be "quite acceptable" to you.