Here are well-regarded vitamin C serums available in India (options across budgets and skin types), plus short reasons and where to buy:

Top picks

• Plum 15% Vitamin C Face Serum — stable ethyl-ascorbic formula, lightweight and very popular in India (good balance of potency and tolerance). (plumgoodness.com, nykaa.com)
• Minimalist Skin-Brightening Vitamin C (16% ethyl ascorbic acid) — high-strength, dermatologist‑style formula at an affordable price. (amazon.in, dermatocare.com)
• Klairs Freshly Juiced Vitamin Drop — lower‑concentration, beginner/sensitive‑skin friendly pure vitamin C option (well-reviewed in India). (nykaa.com)
• The Derma Co. 15% Vitamin C Serum — dermatologist‑targeted brightening serum (good for pigmentation). (amazon.in)
• Dot & Key / Dot & Key Glow Revealing Vitamin C Serums — hydrating, fruit-derived vitamin C options with added hyaluronic/niacinamide (budget‑friendly, widely stocked). (nykaa.com, amazon.in)
• LAKMÉ 9to5 Vit C+ Serum — very budget-friendly, easy-to-find option with Kakadu plum extract (good entry-level pick). (lakmeindia.com)

Which to pick by skin type

• Sensitive or barrier‑compromised: start with gentler derivatives (ethyl ascorbic acid, sodium ascorbyl phosphate or lower % L‑ascorbic) — e.g., Klairs, Plum (ethyl derivative) or SAP‑based serums. (nykaa.com, byrdie.com, beminimalist.co)
• Oily / acne‑prone: look for water‑based, non‑comedogenic formulas and options that include hyaluronic or SAP; try The Derma Co., Dot & Key, or Plum. (amazon.in, nykaa.com, plumgoodness.com)
• Pigmentation / more aggressive brightening: higher % L‑ascorbic or stabilized formulas with ferulic/vitamin E (e.g., Minimalist 16%, some ferulic combos) can be more effective but may irritate—use cautiously. (amazon.in, dermatocare.com)
• Tight budget / daily maintenance: Lakmé 9to5 Vit C+, Plum or Dot & Key give decent daily brightening without high cost. (lakmeindia.com, nykaa.com)

Quick buying & usage tips (important)

• Start low and patch test: introduce vitamin C gradually (every other day) to check tolerance. (healthaccess.com)
• Use in the morning under sunscreen: vitamin C boosts antioxidant protection but is not a substitute for SPF—apply sunscreen after your serum. (realsimple.com)
• Be careful mixing actives: avoid using strong vitamin C together with retinol or strong AHAs/BHAs at the same time to reduce irritation; stagger them (C in AM, retinoid at night). (allure.com, amp.cnn.com)
• Packaging & storage: pick well‑packaged (opaque/airless or amber bottles) formulas and store in a cool, dry place to slow oxidation; discard if it darkens or smells off. (ningen.com, amazon.in)
• Prefer stable derivatives if you don’t want frequent oxidation: ethyl ascorbic acid, ascorbyl glucoside or sodium ascorbyl phosphate are more stable/less irritating than raw L‑ascorbic acid. (beminimalist.co, byrdie.com)

If you tell me your skin type (oily, dry, combination, sensitive) and main goal (glow, fade dark spots, anti‑ageing), I can narrow this to the single best pick and an exact routine.