Why were the balkans known as the powder king of europe in the early 1900s

The Balkans region of Europe was called the 'Powder Keg' because they had many different competing nationalities, ethnic groups, and allegiances in their region. It was said that a match could set off the 'powder' that would impact the whole continent of Europe.

worldwide, 780 million people do not have access to an improved water source. an estimated 2.5 billion people lack access to improved sanitation (more than 35% of the world's population)