Regard is traditionally used in the singular in the phrase in regard (not in regards) to. Regarding and as regards are also standard in the sense "with reference to."
Kenneth G. Wilson (1923-). The Columbia Guide to Standard American English. 1993.
regarding, as regards, in regard(s) to, with regard(s) to
In and with regard to, regarding, and as regards are all Standard, synonymous prepositions, slightly longer and more varied than but meaning much the same as about and concerning: I spoke to him regarding [as regards, in regard to, wi