Dar es Salaam, Tanzania (CNN) -- An estimated 3 billion people -- nearly half the world's population -- still use an open fire as their primary source of energy for cooking and heating.

But there's a problem: the smoke.

"You have respiratory issues, lung disease, you've got pneumonia, and you've got longer-term issues like cancer and heart disease as well that can result from exposure to indoor air pollution," said Radha Muthiah, executive director of the Global Alliance for Clean Cookstoves.

As a child growing up during the Korean War, I studied by candlelight. Electric conveniences such as refrigerators and fans were largely unknown. Yet within my lifetime, that reality changed utterly. Easy access to energy opened abundant new possibilities for my family and my nation.
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