a) Write a letter to your friend inviting him/her to your birthday party. [3] b) Write a short paragraph on the causes of water pollution. [2]

Sender's address & dateBaneswor, KathmanduDate: 2070/03/15

SalutationDear Ramesh

GreetingI hope this letter finds you in good health and high spirits.

Body

I am writing to invite you to my birthday celebration, which will be held on **2070/03/25 (Sunday)** at my residence in Baneshwor, Kathmandu. The party will start at **5:00 PM** and will include a variety of fun activities, delicious food, and music to make the day memorable.

Your presence would mean a lot to me, as I have always cherished our friendship and the joyful moments we have shared. I have planned a small gathering with close friends, and I would be honored if you could join us. Please let me know if you can make it, so I can arrange for your favorite snacks and drinks.

The address of my home is: **House No. 45, Baneshwor-12, Kathmandu**. You can reach me at **9800123456** if you need any further details or assistance. I look forward to celebrating this special day with you and creating more beautiful memories together.

Thank you for considering my invitation. I hope to see you soon and share the joy of my birthday with you.

Closing & signatureWith warm regardsYour friendSarita Shrestha

Causes of Water Pollution

Water pollution is a serious environmental issue that affects both human health and ecosystems. Several factors contribute to this problem, which can be broadly categorized into natural and human-induced causes.

Natural Causes:

• Erosion: Natural processes like wind and water erosion can carry soil and minerals into water bodies, altering their chemical composition.
• Volcanic Eruptions: These can introduce harmful substances like sulfur and ash into water sources, making them unsafe for consumption.

Human-Induced Causes:

• Industrial Waste: Factories and industries often discharge toxic chemicals, heavy metals, and other pollutants into rivers and lakes without proper treatment. For example, untreated wastewater from textile industries can contain harmful dyes and acids.
• Agricultural Runoff: The excessive use of fertilizers and pesticides in farming leads to nutrient pollution (eutrophication) and chemical contamination of water bodies. Rainwater washes these chemicals into nearby rivers and lakes.
• Sewage and Wastewater: Improper disposal of domestic sewage and wastewater from households and cities contaminates water sources with pathogens like bacteria and viruses, causing waterborne diseases.
• Oil Spills: Accidental or intentional spills of oil and petroleum products from ships, offshore drilling, or industrial accidents severely pollute water, harming marine life and ecosystems.
• Plastic Pollution: The disposal of plastic waste into water bodies chokes aquatic life and degrades water quality over time.
• Mining Activities: Mining operations release heavy metals like mercury, lead, and arsenic into water sources, posing serious health risks to humans and wildlife.

Water pollution not only disrupts aquatic ecosystems but also affects human health by spreading diseases like cholera, dysentery, and typhoid. It is crucial to adopt sustainable practices, enforce strict environmental regulations, and promote awareness to mitigate this growing problem.