Sec. 43B applies to both employee and employer's contribution to PF and ESI

The High Court of Allahabad held that Assessee deposited contributions towards provident fund
and ESI before due date of filing of return, deductions allowable.
Sagun Foundry (P.) Ltd. v. Commissioner of Income-tax, Kanpur* [2017] 78 taxmann.com 47 (Allahabad)