The Global South faces unique challenges in achieving digital inclusion due to a heavy reliance on mobile devices for internet access and the prevalence of slow or unreliable networks. While numerous studies have investigated web accessibility within specific sectors such as education, healthcare, and government services, these efforts have been largely constrained to individual countries or narrow contexts, leaving a critical gap in cross-regional, large-scale analysis. This paper addresses this gap by conducting the first large-scale comparative study of mobile web accessibility across the Global South. In this work, we evaluate 100,000 websites from 10 countries in the Global South to provide a comprehensive understanding of accessibility practices in these regions. Our findings reveal that websites from countries with strict accessibility regulations and enforcement tend to adhere better to Web Content Accessibility Guidelines (WCAG) guidelines. However, accessibility violations impact different disability groups in varying ways. Blind and low-vision individuals in the Global South are disproportionately affected, as only 40% of the evaluated websites meet critical accessibility guidelines. This significant shortfall is largely due to developers frequently neglecting to implement valid alt text for images and ARIA descriptions, which are essential specification mechanisms in the HTML standard for the effective operation of screen readers.