Concept: Non-structural measures are those disaster management measures which do not involve physical construction. These include laws, policies, land-use planning, zoning regulations, awareness, building codes, training, and institutional guidelines.
Step 1: Understanding non-structural measures.
Non-structural disaster management measures are preventive and planning-based measures. They reduce disaster risk without constructing physical structures like dams, embankments, shelters, or retaining walls.
\[
\text{Non-structural measures} = \text{Rules + Planning + Zoning + Codes + Awareness}
\]
Step 2: Checking the given options.
Flood plain zoning is a non-structural measure because it controls construction and settlement in flood-prone areas.
Techno-legal provisions like BIS codes are also non-structural because they guide safe construction through legal and technical standards.
Amendment of land-use and zoning regulation is also a non-structural measure because it controls how land should be used.
Step 3: Finding the option that does not directly represent a specific non-structural planning measure.
Strengthening the enforcement mechanism is more of an administrative action. It supports implementation, but it is not itself a specific non-structural measure like zoning, building codes, or land-use regulation.
Therefore, the correct answer is Strengthening the enforcement mechanism.