Owing to his illness he could not come to school.
It was due to his illness he could not come to school
Due to his illness he could not come to school
I know that the statements 1 and 2 are correct. But what about the third one? Is it acceptable in standard English?
They are all OK. Although I would add some commas but that is my preference.
In items 2 & 3 we are using Due to mean because of.So lets do a substitution to see if the sentence is still OK.
It was due to his illness, (that) he could not come to school
It was because of his illness, (that) he could not come to school
Due to his illness, he could not come to school
Because of his illness, he could not come to school
Note; The use of That as a conjunction is optional although to me it sounds more comfortable to use that in the second example
that Link E.E.D.
conjunction: used to introduce a clause that reports something or gives further information, although it can often be left out:
The second sentence is not quite correct (It was due to his illness that he could not...) and has a strong emphasis on the reason (unlike the other two). In sentence 3 a comma is needed after 'Due to his illness'.
