ETL data pipelines play a crucial role in machine learning systems by streamlining the processes of extracting, transforming, and loading data, which enhances data quality, integration, and availability for model training. The article highlights the significance of ETL pipelines in ensuring the accuracy and effectiveness of ML models, providing data scientists with clean, reliable data, and enabling organizations to derive insights from complex datasets. It distinguishes between general data pipelines and ETL pipelines, emphasizing the specific role of ETL in transforming raw data into a structured format suitable for ML applications. Various types of ETL pipelines, such as batch, real-time, incremental, cloud, and hybrid ETL, cater to different business needs and data processing requirements. The article also outlines the steps to build an ETL pipeline using Apache Airflow, from setting up the environment to monitoring and managing the workflow, along with best practices for constructing scalable and efficient ETL pipelines, which include data quality assurance, automation, and version control. These pipelines are essential for integrating machine learning models with data analytics, empowering organizations with advanced predictive capabilities.