More than 50% of the world's largest countries and cities depend on groundwater for their daily needs. In particular, 80% of the largest cities in the Middle East, South Asia, and Central Asia rely on groundwater for drinking, irrigation, and industrial uses. In this review, we discuss the impacts of climate change on groundwater, various sources of arsenic contamination in groundwater, the current status of arsenic contamination in selected major countries in South Asia, the integrated application of remote sensing and machine learning methods in arsenic detection, and novel treatment techniques for the removal of arsenic from groundwater. In this study, we found that unconsolidated aquifers and coastal aquifers are the major sources of arsenic contamination in groundwater. On the basis of the present literature survey, the majorly affected coastal aquifers are 11 coastal provinces in Bangladesh, 9 provinces in Vietnam, 3 provinces in Cambodia, and 2 provinces in Thailand. In view of health impacts, the continuous consumption of arsenic-contaminated groundwater has serious health impacts, such as the detection of cancer in the skin, lungs, kidneys, and bladder; heart disease; hypertension; increased blood pressure; and nervous system problems. The advanced satellite images with genetic algorithm, support vector machine, and artificial neural network are highly efficient methods to detect arsenic in groundwater. Treatment techniques, namely, adsorption, membrane filtration, electrocoagulation, and ion-exchange processes, are more significant and effective methods for removing arsenic from groundwater. The lack of awareness among people and strategies for water management systems are the primary reasons for groundwater contamination in many parts of South Asian countries, and very few policies have been implemented at the international level to reduce arsenic contamination in groundwater. The present detailed review will be helpful to policymakers and nongovernmental organizations to take remedial measures and conduct awareness programs in rural and semiarid zones.