ZOS - "As such, coming in Update 35, we are increasing the duration of many of these effects in game, primarily damage over time, buffs, and debuffs. By extending the duration, we hope to reduce the stress of many combat rotations, allowing for you to focus more on the action in front of you rather than the action of juggling buffs and debuffs on your ability bar and making the game far more accessible. "

Also ZOS - "5 – When you apply a Major Debuff to an enemy, remove a Major Buff with a duration from the target. When you apply a Minor Debuff to an enemy, remove a Minor Buff with a duration from the target. These effects can both occur once every 2 seconds."