Auma Obama, an older half sister of former President Barack Obama, was tear-gassed on Tuesday while being interviewed live on CNN during protests in Nairobi, the Kenyan capital. The protests were against the passage of a finance bill that raises taxes on many basic goods.

Ms. Obama was with a group of protesters carrying placards when a CNN reporter approached her.

“I am here because — look at what’s happening,” she told the interviewer. “Young Kenyans are demonstrating for their rights. They are demonstrating with flags and banners.”

Ms. Obama then began choking in a spreading cloud of tear gas lobbed by the police.

“I can’t even see anymore,” she said. “We are being tear-gassed.”

Ms. Obama grew up in Kenya and returned there as a community activist after studying and living in Germany and the United Kingdom. Her foundation in Kenya, Sauti Kuu, or Powerful Voices, serves children and young people, particularly from urban slums and rural communities.

Ms. Obama had earlier posted photos of herself at the protest on social media. As thousands marched to Parliament, police used tear gas and water cannons and opened fire. At least five people were killed and 31 people were wounded, according to several civic groups.