Bangladesh, Sept. 16 -- In the fertile farmlands of northwest Nigeria, fields of cotton, grains, beans, and nuts stretch across Kano State, sustaining millions of smallholder farmers. These farms are the backbone of local livelihoods. Yet, hidden beneath the promise of harvest lies a troubling contradiction: the continued presence of toxic herbicides that Nigeria has officially banned, but which still flow into the country through loopholes, weak enforcement, and foreign corporate influence.

For farmers like 56-year-old Abdulwahab Tsoho Adamu of Tassa village, the dilemma is deeply personal. Adamu grows maize and beans and knows firsthand the appeal of the herbicides paraquat and atrazine-both declared unsafe by Nigerian regulators. Desp...