It is established that creating low cost homes is a good oppportunity and the size is gigantic even if partly successful. It is also backed by govt intent. There seems to be a competition b/w state govts with gujarat taking the lead.
Some themes that emerge after talking to purchasing managers are as follows
Granites - staircases, pathways, frames etc will need granite . Shahbad stone is the cheapest.
Doors - readymade doors. Bloom decor and euro doors are some names that manufacture cost effective doors.
Fabrication big opportunity. MS steel cheaper so Grills and window frames in ms steel amd not ss steel.
Paints - dry distemper cheapest. Some names like Jotun were mentioned.
Pumps and panels. Both LT panels and HT panels.
Firefighting equipment is a mandatory for any project and rajkot is the market leader in manufacturing. So sprinklers, hydrants, strainers , pipelines etc
Transformers - since lots of homes in one project higher capacity transformers will be needed
Wires and switches - some names polycab havells vinay wires
Lifts - depending upon the state they are mandatory beyond certain floors (+5 in mah). Some names like omega in the low cost category
In addn there is the usual cement steel bricks etc
There are many others like tiles and sanitaryware fittings but it seems china is doing a good job supplying those. So unsure about opportunity there but still the opportunity wont completely bypass the organized players. They will benefit.
It is in the interest of developers to do affordable housing even if margins less because many other benefits like faster approvals, greater fsi, IT benefits etc. It will be easier with developer buy in. However govt can very well do this on their own so investing with developers not a good idea as no clarity on plans. However some developers exist with fully paid for land in locations that are tailormade for AH schemes.
By no means this is the complete set of opportunities but still lots of time to flesh out specific areas.