Phase-out of incandescent light bulbs were no longer available from European sources. Russia is phasing out incandescent light bulbs. The production of lamps of 100 watt and more is banned. There are also discussions to ban light bulbs of 50 watts and more. Switzerland banned the sale of all light bulbs of the Energy Efficiency Class F and G, which affects a few types of incandescent light bulbs. Most normal light bulbs are of Energy Efficiency Class E, and the Swiss regulation has exceptions for various kinds of special-purpose and decorative bulbs. In line with EU rules, Switzerland banned the import and manufacture of halogen
Incandescent light bulb envelope. From time to time, the operator would remove the bulb and shake it, allowing the tungsten powder to scrub off most of the tungsten that had condensed on the interior of the envelope, removing the blackening and brightening the lamp again. The halogen lamp reduces uneven evaporation of the filament and eliminates darkening of the envelope by filling the lamp with a halogen gas at low pressure, rather than an inert gas. The halogen cycle increases the lifetime of the bulb and prevents its darkening by redepositing tungsten from the inside of the bulb back onto the filament. The