Shedding light on local development: Unveiling spatial dynamics from infrastructure implementation through nighttime lights in the Nacala corridor, Mozambique

The increased use of nighttime lights (NTL) to assess infrastructure implementation and socioeconomic development highlights the potential of this open data source, often used as a proxy indicator of economic dynamics. Many studies focus on supra-national levels and the quantification of light emissions, generating assumptions regarding development. However, fewer studies address the characterization of socio-spatial dynamics at the local level. This research analyses the Nacala corridor in Mozambique, aiming to challenge the assumption that increasing NTL levels equals local development. We qualify and contextualize the types of activities identified by nighttime light anomalies. Using data cubes with 10-year seasonal NTL emissions, we identified anomalies in the time series of 17 out of 74 settlements and subsequently analyzed them with very high-resolution images. Among these settlements, we identified soil extraction, quarrying, or industries in 13 cases. Finally, we compared the results with household surveys indicating that during the period, the population had no significant increase in access to energy. We conclude that the NTL time series can effectively portray infrastructure-driven activities, such as surface mining and industry, in the context of the Corridor. However, the assumption that local development is linked with an increase in NTL in non-urbanized areas can be misleading without qualitative analysis. The activities that are the source of radiance can be illicit, not socially adopted, economically concentrated, and/or environmentally harmful.