The Public Works Department (PWD) has initiated a new construction approach for storm water drains across Delhi, mandating the use of precast drain boxes in place of the conventional cast-in-situ method, an official aware of the development said on Saturday. Precast drain boxes improve durability, reduce construction time, and minimise on-site pollution. HT PHOTO The shift is a part of an ongoing citywide drain remodelling exercise aligned with the drainage master plan, under which 20 tenders have already been floated. Work has commenced in Shalimar Bagh and is expected to expand to other parts of the city in phases, the official said. Faster execution, improved durability Precast drain boxes improve durability, reduce construction time, and minimise on-site pollution. Moreover, unlike the traditional cast-in-situ method, where raw materials such as cement, sand and aggregates are mixed and poured directly at the construction site, precast drain boxes are manufactured in controlled factory settings. Also read | PWD plans to renovate ‘jinxed’ Shamnath Marg bungalow in Delhi “The biggest advantage of precast drain boxes is the uniform quality …