DTCP approval (from the Directorate of Town and Country Planning) applies to land layouts — it confirms that a plotted development follows zoning rules, has proper road widths, drainage, and open space allocation before any plot is sold.
RERA registration, by contrast, applies to real estate projects and promoters — both plotted developments and built structures. It's a consumer-protection layer that requires promoters to disclose project timelines, escrow a portion of buyer payments for construction costs, and publish regular progress updates.
In practice, a well-run plotted layout in Andhra Pradesh should carry both: DTCP approval for the layout itself, and RERA registration for the promoter selling it. If a seller can only show you one, ask why.
Neither approval guarantees a good investment on its own, but the absence of either is a real warning sign worth walking away from.