After studying the entire thread so far, it seems that there was a proposal to create a wearable mask, where the airflow was treated under UV radiation in order to control live virus passage.
But it is not clear whether this objective is either achieved or feasible. The last post refers to creating a quick and dirty solution using evenly distributed carbonated sodium salts on porous paper, and this filter also needed to be applied to a 3D printed holder.
Given that the distribution of 3D printing resources is uneven and very low, neither solution seems particularly practical for lockdown situations, in India.
It might appear, rather, that it is best to attempt to get hold of one or other variant of a commercial N95 mask, and attempt to keep this in sterile condition over a period of regular use, or to apply carbonated salt treated paper to a cloth surgical mask, and limit its use to a minimal period, ie one time use only, while cleaning (washing) the surgical mask repeatedly with alcohol based sanitizer in order to extend its safe use period.