Sodium lights are also known as low-pressure sodium lamps or high-pressure sodium lamps. They are commonly used for outdoor lighting, especially in streetlights and parking lots. Other synonyms for sodium lights include yellow lights, sodium-vapor lights, or even just streetlights. However, not all streetlights are sodium lights, as some cities have started using LED lights which are much more energy-efficient. Sodium lights can be identified by their distinctive yellow or orange glow, which is caused by the sodium vapor in the lamp. While they are still used in many places, sodium lights are gradually being replaced by other lighting options which are more eco-friendly and cost-effective.