What emergency measure should be taken in case of a gas leak with LPG or CNG?

The appropriate emergency measure to take in the event of a gas leak with LPG or CNG is to evacuate the area immediately. This action is crucial because these gases are highly flammable and can pose serious risks to life and safety. Evacuation allows individuals to move to a safe distance away from potential sources of ignition and reduces the likelihood of an explosion or fire caused by accumulated gas.

While other actions like sealing windows or turning off electrical devices may seem prudent in other situations, they are either ineffective or could potentially worsen the situation in the case of a gas leak. Using a fan for circulation is also not advisable, as it could spread the gas more quickly through the space, increasing the danger. Immediate evacuation is the safest and most effective response to protect lives in the event of a gas leak.