Blockchain technology has gained attention to not only tech realm but also makes attention from various sectors like education, health, insurance, finance, transportation, supply chain, agriculture, government, E-commerce etc.… The decentralized, trusted, secure, transparent, and immutable features of blockchain become particularly prominent when integrated with machine learning and the Internet of Things (IoT). However, it faces some challenges but out of them the scalability challenge is the most affecting challenge. As its popularity has prompted the research community to investigate and analyze its challenges. The objective of this study is to address the scalability challenge by examining its affecting parameters. The study further provides a comprehensive classification of recent solutions based on parameters such as methodology or techniques, architecture, types of network, and consensus mechanisms etc.… The conclusion includes recommendations and outlines potential avenues for future research that catering to the research community. This work aims to offer valuable classified information on the blockchain scalability challenge, solutions and different blockchain applications.