There are several sectors and industries that are ripe for disruption and innovation in the field of sustainability. Here are a few examples:

1. Energy: The energy sector is a major contributor to greenhouse gas emissions, and there is a growing demand for cleaner and more renewable sources of energy. Sustainable startups could focus on developing new renewable energy technologies such as solar, wind, or geothermal, or on improving energy efficiency in buildings and transportation.
2. Agriculture: Agriculture is another sector with significant environmental impact, particularly when it comes to water use, soil health, and biodiversity. Sustainable startups could focus on developing more sustainable farming practices, such as regenerative agriculture or vertical farming, or on creating new plant-based or lab-grown alternatives to animal products.
3. Fashion: The fashion industry is one of the largest polluters in the world, with significant environmental impact throughout the supply chain. Sustainable startups could focus on developing new sustainable materials such as plant-based fabrics or recycled textiles, or on creating circular business models that reduce waste and encourage recycling.
4. Transportation: The transportation sector is another major contributor to greenhouse gas emissions, particularly in the form of fossil-fuel-powered vehicles. Sustainable startups could focus on developing new electric or hydrogen-powered vehicles, or on creating more sustainable transportation systems such as bike-sharing or car-sharing services.
5. Waste management: The management of waste is a significant environmental challenge, particularly when it comes to plastic waste. Sustainable startups could focus on developing new recycling technologies, creating circular business models that reduce waste, or on creating new sustainable packaging materials.