Step 1: Problem in fire safety.
In case of fire, smoke spread is a bigger killer than the flames themselves. It causes suffocation, reduces visibility, and prevents safe evacuation. Enclosed fire staircases in high-rise buildings must be kept free of smoke at all times.
Step 2: Principle of smoke prevention.
Smoke naturally drifts from high-pressure zones (fire-affected areas) to low-pressure zones (staircases). If we can maintain higher air pressure inside the staircase shaft, smoke will not be able to enter.
Step 3: Definition of pressurization.
Pressurization means mechanical fans continuously pump fresh air into the staircase shaft, ensuring:
\[
P_{\text{staircase}} > P_{\text{adjacent rooms}}
\]
Thus, airflow direction is always outward from staircase to rooms, preventing smoke ingress.
Step 4: Elimination of wrong options.
- (A) Polarization → electrical phenomenon, irrelevant here.
- (C) Perpetuation → means continuation, not applicable to fire design.
- (D) Fumigation → use of chemicals for pest control, unrelated.
Step 5: Conclude.
Only pressurization directly solves the problem.
Final Answer: \[ \boxed{\text{Pressurization}} \]
Match the following Planning Strategies in Group-I to their corresponding descriptions in Group-II.

A four-arm uncontrolled un-signaled urban intersection of both-way traffic is illustrated in the figure. Vehicles approaching the intersection from the directions A, B, C, and D can move to either left, right, or continue in straight direction. No U-turn is allowed. In the given situation, the maximum number of vehicular crossing conflict points for this intersection is _________ (answer in integer)

An individual chooses a transport mode for a particular trip based on three attributes i.e., cost of journey (X), In-vehicle travel time to reach destination (Y), and Out-of-vehicle time taken to access mode at respective stops (Z). The values for these attributes for three modes Rail, Bus and Para-transit are given in the table. If the general utility (U) equation is \( U = - 0.5 \times X - 0.3 \times Y - 0.4 \times Z \), using the Logit model, the estimated probability of choosing Bus is _________ (rounded off to two decimal places).
